diff --git a/quiche/quic/core/http/capsule.cc b/quiche/quic/core/http/capsule.cc
index 8f653f1..fc062b9 100644
--- a/quiche/quic/core/http/capsule.cc
+++ b/quiche/quic/core/http/capsule.cc
@@ -22,10 +22,12 @@
 
 std::string CapsuleTypeToString(CapsuleType capsule_type) {
   switch (capsule_type) {
+    case CapsuleType::DATAGRAM:
+      return "DATAGRAM";
     case CapsuleType::LEGACY_DATAGRAM:
       return "LEGACY_DATAGRAM";
-    case CapsuleType::DATAGRAM_WITHOUT_CONTEXT:
-      return "DATAGRAM_WITHOUT_CONTEXT";
+    case CapsuleType::LEGACY_DATAGRAM_WITHOUT_CONTEXT:
+      return "LEGACY_DATAGRAM_WITHOUT_CONTEXT";
     case CapsuleType::CLOSE_WEBTRANSPORT_SESSION:
       return "CLOSE_WEBTRANSPORT_SESSION";
     case CapsuleType::ADDRESS_REQUEST:
@@ -45,6 +47,12 @@
 
 Capsule::Capsule(CapsuleType capsule_type) : capsule_type_(capsule_type) {
   switch (capsule_type) {
+    case CapsuleType::DATAGRAM:
+      static_assert(std::is_standard_layout<DatagramCapsule>::value &&
+                        std::is_trivially_destructible<DatagramCapsule>::value,
+                    "All inline capsule structs must have these properties");
+      datagram_capsule_ = DatagramCapsule();
+      break;
     case CapsuleType::LEGACY_DATAGRAM:
       static_assert(
           std::is_standard_layout<LegacyDatagramCapsule>::value &&
@@ -52,13 +60,14 @@
           "All inline capsule structs must have these properties");
       legacy_datagram_capsule_ = LegacyDatagramCapsule();
       break;
-    case CapsuleType::DATAGRAM_WITHOUT_CONTEXT:
+    case CapsuleType::LEGACY_DATAGRAM_WITHOUT_CONTEXT:
       static_assert(
-          std::is_standard_layout<DatagramWithoutContextCapsule>::value &&
+          std::is_standard_layout<LegacyDatagramWithoutContextCapsule>::value &&
               std::is_trivially_destructible<
-                  DatagramWithoutContextCapsule>::value,
+                  LegacyDatagramWithoutContextCapsule>::value,
           "All inline capsule structs must have these properties");
-      datagram_without_context_capsule_ = DatagramWithoutContextCapsule();
+      legacy_datagram_without_context_capsule_ =
+          LegacyDatagramWithoutContextCapsule();
       break;
     case CapsuleType::CLOSE_WEBTRANSPORT_SESSION:
       static_assert(
@@ -86,8 +95,9 @@
 void Capsule::Free() {
   switch (capsule_type_) {
     // Inlined capsule types.
+    case CapsuleType::DATAGRAM:
     case CapsuleType::LEGACY_DATAGRAM:
-    case CapsuleType::DATAGRAM_WITHOUT_CONTEXT:
+    case CapsuleType::LEGACY_DATAGRAM_WITHOUT_CONTEXT:
     case CapsuleType::CLOSE_WEBTRANSPORT_SESSION:
       // Do nothing, these are guaranteed to be trivially destructible.
       break;
@@ -108,6 +118,13 @@
 Capsule::~Capsule() { Free(); }
 
 // static
+Capsule Capsule::Datagram(absl::string_view http_datagram_payload) {
+  Capsule capsule(CapsuleType::DATAGRAM);
+  capsule.datagram_capsule().http_datagram_payload = http_datagram_payload;
+  return capsule;
+}
+
+// static
 Capsule Capsule::LegacyDatagram(absl::string_view http_datagram_payload) {
   Capsule capsule(CapsuleType::LEGACY_DATAGRAM);
   capsule.legacy_datagram_capsule().http_datagram_payload =
@@ -116,10 +133,10 @@
 }
 
 // static
-Capsule Capsule::DatagramWithoutContext(
+Capsule Capsule::LegacyDatagramWithoutContext(
     absl::string_view http_datagram_payload) {
-  Capsule capsule(CapsuleType::DATAGRAM_WITHOUT_CONTEXT);
-  capsule.datagram_without_context_capsule().http_datagram_payload =
+  Capsule capsule(CapsuleType::LEGACY_DATAGRAM_WITHOUT_CONTEXT);
+  capsule.legacy_datagram_without_context_capsule().http_datagram_payload =
       http_datagram_payload;
   return capsule;
 }
@@ -160,12 +177,15 @@
   Free();
   capsule_type_ = other.capsule_type_;
   switch (capsule_type_) {
+    case CapsuleType::DATAGRAM:
+      datagram_capsule_ = other.datagram_capsule_;
+      break;
     case CapsuleType::LEGACY_DATAGRAM:
       legacy_datagram_capsule_ = other.legacy_datagram_capsule_;
       break;
-    case CapsuleType::DATAGRAM_WITHOUT_CONTEXT:
-      datagram_without_context_capsule_ =
-          other.datagram_without_context_capsule_;
+    case CapsuleType::LEGACY_DATAGRAM_WITHOUT_CONTEXT:
+      legacy_datagram_without_context_capsule_ =
+          other.legacy_datagram_without_context_capsule_;
       break;
     case CapsuleType::CLOSE_WEBTRANSPORT_SESSION:
       close_web_transport_session_capsule_ =
@@ -199,12 +219,16 @@
     return false;
   }
   switch (capsule_type_) {
+    case CapsuleType::DATAGRAM:
+      return datagram_capsule_.http_datagram_payload ==
+             other.datagram_capsule_.http_datagram_payload;
     case CapsuleType::LEGACY_DATAGRAM:
       return legacy_datagram_capsule_.http_datagram_payload ==
              other.legacy_datagram_capsule_.http_datagram_payload;
-    case CapsuleType::DATAGRAM_WITHOUT_CONTEXT:
-      return datagram_without_context_capsule_.http_datagram_payload ==
-             other.datagram_without_context_capsule_.http_datagram_payload;
+    case CapsuleType::LEGACY_DATAGRAM_WITHOUT_CONTEXT:
+      return legacy_datagram_without_context_capsule_.http_datagram_payload ==
+             other.legacy_datagram_without_context_capsule_
+                 .http_datagram_payload;
     case CapsuleType::CLOSE_WEBTRANSPORT_SESSION:
       return close_web_transport_session_capsule_.error_code ==
                  other.close_web_transport_session_capsule_.error_code &&
@@ -227,17 +251,22 @@
 std::string Capsule::ToString() const {
   std::string rv = CapsuleTypeToString(capsule_type_);
   switch (capsule_type_) {
+    case CapsuleType::DATAGRAM:
+      absl::StrAppend(
+          &rv, "[",
+          absl::BytesToHexString(datagram_capsule_.http_datagram_payload), "]");
+      break;
     case CapsuleType::LEGACY_DATAGRAM:
       absl::StrAppend(&rv, "[",
                       absl::BytesToHexString(
                           legacy_datagram_capsule_.http_datagram_payload),
                       "]");
       break;
-    case CapsuleType::DATAGRAM_WITHOUT_CONTEXT:
+    case CapsuleType::LEGACY_DATAGRAM_WITHOUT_CONTEXT:
       absl::StrAppend(
           &rv, "[",
           absl::BytesToHexString(
-              datagram_without_context_capsule_.http_datagram_payload),
+              legacy_datagram_without_context_capsule_.http_datagram_payload),
           "]");
       break;
     case CapsuleType::CLOSE_WEBTRANSPORT_SESSION:
@@ -297,12 +326,16 @@
       static_cast<uint64_t>(capsule.capsule_type()));
   QuicByteCount capsule_data_length;
   switch (capsule.capsule_type()) {
+    case CapsuleType::DATAGRAM:
+      capsule_data_length =
+          capsule.datagram_capsule().http_datagram_payload.length();
+      break;
     case CapsuleType::LEGACY_DATAGRAM:
       capsule_data_length =
           capsule.legacy_datagram_capsule().http_datagram_payload.length();
       break;
-    case CapsuleType::DATAGRAM_WITHOUT_CONTEXT:
-      capsule_data_length = capsule.datagram_without_context_capsule()
+    case CapsuleType::LEGACY_DATAGRAM_WITHOUT_CONTEXT:
+      capsule_data_length = capsule.legacy_datagram_without_context_capsule()
                                 .http_datagram_payload.length();
       break;
     case CapsuleType::CLOSE_WEBTRANSPORT_SESSION:
@@ -365,19 +398,29 @@
     return {};
   }
   switch (capsule.capsule_type()) {
+    case CapsuleType::DATAGRAM:
+      if (!writer.WriteStringPiece(
+              capsule.datagram_capsule().http_datagram_payload)) {
+        QUIC_BUG(datagram capsule payload write fail)
+            << "Failed to write DATAGRAM CAPSULE payload";
+        return {};
+      }
+      break;
     case CapsuleType::LEGACY_DATAGRAM:
       if (!writer.WriteStringPiece(
               capsule.legacy_datagram_capsule().http_datagram_payload)) {
-        QUIC_BUG(datagram capsule payload write fail)
+        QUIC_BUG(datagram legacy capsule payload write fail)
             << "Failed to write LEGACY_DATAGRAM CAPSULE payload";
         return {};
       }
       break;
-    case CapsuleType::DATAGRAM_WITHOUT_CONTEXT:
-      if (!writer.WriteStringPiece(capsule.datagram_without_context_capsule()
-                                       .http_datagram_payload)) {
-        QUIC_BUG(datagram capsule payload write fail)
-            << "Failed to write DATAGRAM_WITHOUT_CONTEXT CAPSULE payload";
+    case CapsuleType::LEGACY_DATAGRAM_WITHOUT_CONTEXT:
+      if (!writer.WriteStringPiece(
+              capsule.legacy_datagram_without_context_capsule()
+                  .http_datagram_payload)) {
+        QUIC_BUG(datagram legacy without context capsule payload write fail)
+            << "Failed to write LEGACY_DATAGRAM_WITHOUT_CONTEXT CAPSULE "
+               "payload";
         return {};
       }
       break;
@@ -539,12 +582,16 @@
   QuicDataReader capsule_data_reader(capsule_data);
   Capsule capsule(static_cast<CapsuleType>(capsule_type64));
   switch (capsule.capsule_type()) {
+    case CapsuleType::DATAGRAM:
+      capsule.datagram_capsule().http_datagram_payload =
+          capsule_data_reader.ReadRemainingPayload();
+      break;
     case CapsuleType::LEGACY_DATAGRAM:
       capsule.legacy_datagram_capsule().http_datagram_payload =
           capsule_data_reader.ReadRemainingPayload();
       break;
-    case CapsuleType::DATAGRAM_WITHOUT_CONTEXT:
-      capsule.datagram_without_context_capsule().http_datagram_payload =
+    case CapsuleType::LEGACY_DATAGRAM_WITHOUT_CONTEXT:
+      capsule.legacy_datagram_without_context_capsule().http_datagram_payload =
           capsule_data_reader.ReadRemainingPayload();
       break;
     case CapsuleType::CLOSE_WEBTRANSPORT_SESSION:
diff --git a/quiche/quic/core/http/capsule.h b/quiche/quic/core/http/capsule.h
index 3d83a55..c7866a8 100644
--- a/quiche/quic/core/http/capsule.h
+++ b/quiche/quic/core/http/capsule.h
@@ -22,8 +22,9 @@
 
 enum class CapsuleType : uint64_t {
   // Casing in this enum matches the IETF specifications.
+  DATAGRAM = 0x00,             // RFC 9297.
   LEGACY_DATAGRAM = 0xff37a0,  // draft-ietf-masque-h3-datagram-04.
-  DATAGRAM_WITHOUT_CONTEXT =
+  LEGACY_DATAGRAM_WITHOUT_CONTEXT =
       0xff37a5,  // draft-ietf-masque-h3-datagram-05 to -08.
   CLOSE_WEBTRANSPORT_SESSION = 0x2843,
   // draft-ietf-masque-connect-ip-03.
@@ -36,10 +37,13 @@
 QUIC_EXPORT_PRIVATE std::ostream& operator<<(std::ostream& os,
                                              const CapsuleType& capsule_type);
 
+struct QUIC_EXPORT_PRIVATE DatagramCapsule {
+  absl::string_view http_datagram_payload;
+};
 struct QUIC_EXPORT_PRIVATE LegacyDatagramCapsule {
   absl::string_view http_datagram_payload;
 };
-struct QUIC_EXPORT_PRIVATE DatagramWithoutContextCapsule {
+struct QUIC_EXPORT_PRIVATE LegacyDatagramWithoutContextCapsule {
   absl::string_view http_datagram_payload;
 };
 struct QUIC_EXPORT_PRIVATE CloseWebTransportSessionCapsule {
@@ -70,16 +74,18 @@
   bool operator==(const RouteAdvertisementCapsule& other) const;
 };
 
-// Capsule from draft-ietf-masque-h3-datagram.
+// Capsule from RFC 9297.
 // IMPORTANT NOTE: Capsule does not own any of the absl::string_view memory it
 // points to. Strings saved into a capsule must outlive the capsule object. Any
 // code that sees a capsule in a callback needs to either process it immediately
 // or perform its own deep copy.
 class QUIC_EXPORT_PRIVATE Capsule {
  public:
+  static Capsule Datagram(
+      absl::string_view http_datagram_payload = absl::string_view());
   static Capsule LegacyDatagram(
       absl::string_view http_datagram_payload = absl::string_view());
-  static Capsule DatagramWithoutContext(
+  static Capsule LegacyDatagramWithoutContext(
       absl::string_view http_datagram_payload = absl::string_view());
   static Capsule CloseWebTransportSession(
       WebTransportSessionError error_code = 0,
@@ -103,6 +109,14 @@
                                                       const Capsule& capsule);
 
   CapsuleType capsule_type() const { return capsule_type_; }
+  DatagramCapsule& datagram_capsule() {
+    QUICHE_DCHECK_EQ(capsule_type_, CapsuleType::DATAGRAM);
+    return datagram_capsule_;
+  }
+  const DatagramCapsule& datagram_capsule() const {
+    QUICHE_DCHECK_EQ(capsule_type_, CapsuleType::DATAGRAM);
+    return datagram_capsule_;
+  }
   LegacyDatagramCapsule& legacy_datagram_capsule() {
     QUICHE_DCHECK_EQ(capsule_type_, CapsuleType::LEGACY_DATAGRAM);
     return legacy_datagram_capsule_;
@@ -111,14 +125,17 @@
     QUICHE_DCHECK_EQ(capsule_type_, CapsuleType::LEGACY_DATAGRAM);
     return legacy_datagram_capsule_;
   }
-  DatagramWithoutContextCapsule& datagram_without_context_capsule() {
-    QUICHE_DCHECK_EQ(capsule_type_, CapsuleType::DATAGRAM_WITHOUT_CONTEXT);
-    return datagram_without_context_capsule_;
+  LegacyDatagramWithoutContextCapsule&
+  legacy_datagram_without_context_capsule() {
+    QUICHE_DCHECK_EQ(capsule_type_,
+                     CapsuleType::LEGACY_DATAGRAM_WITHOUT_CONTEXT);
+    return legacy_datagram_without_context_capsule_;
   }
-  const DatagramWithoutContextCapsule& datagram_without_context_capsule()
-      const {
-    QUICHE_DCHECK_EQ(capsule_type_, CapsuleType::DATAGRAM_WITHOUT_CONTEXT);
-    return datagram_without_context_capsule_;
+  const LegacyDatagramWithoutContextCapsule&
+  legacy_datagram_without_context_capsule() const {
+    QUICHE_DCHECK_EQ(capsule_type_,
+                     CapsuleType::LEGACY_DATAGRAM_WITHOUT_CONTEXT);
+    return legacy_datagram_without_context_capsule_;
   }
   CloseWebTransportSessionCapsule& close_web_transport_session_capsule() {
     QUICHE_DCHECK_EQ(capsule_type_, CapsuleType::CLOSE_WEBTRANSPORT_SESSION);
@@ -154,8 +171,10 @@
     return *route_advertisement_capsule_;
   }
   absl::string_view& unknown_capsule_data() {
-    QUICHE_DCHECK(capsule_type_ != CapsuleType::LEGACY_DATAGRAM &&
-                  capsule_type_ != CapsuleType::DATAGRAM_WITHOUT_CONTEXT &&
+    QUICHE_DCHECK(capsule_type_ != CapsuleType::DATAGRAM &&
+                  capsule_type_ != CapsuleType::LEGACY_DATAGRAM &&
+                  capsule_type_ !=
+                      CapsuleType::LEGACY_DATAGRAM_WITHOUT_CONTEXT &&
                   capsule_type_ != CapsuleType::CLOSE_WEBTRANSPORT_SESSION &&
                   capsule_type_ != CapsuleType::ADDRESS_REQUEST &&
                   capsule_type_ != CapsuleType::ADDRESS_ASSIGN &&
@@ -164,8 +183,10 @@
     return unknown_capsule_data_;
   }
   const absl::string_view& unknown_capsule_data() const {
-    QUICHE_DCHECK(capsule_type_ != CapsuleType::LEGACY_DATAGRAM &&
-                  capsule_type_ != CapsuleType::DATAGRAM_WITHOUT_CONTEXT &&
+    QUICHE_DCHECK(capsule_type_ != CapsuleType::DATAGRAM &&
+                  capsule_type_ != CapsuleType::LEGACY_DATAGRAM &&
+                  capsule_type_ !=
+                      CapsuleType::LEGACY_DATAGRAM_WITHOUT_CONTEXT &&
                   capsule_type_ != CapsuleType::CLOSE_WEBTRANSPORT_SESSION &&
                   capsule_type_ != CapsuleType::ADDRESS_REQUEST &&
                   capsule_type_ != CapsuleType::ADDRESS_ASSIGN &&
@@ -178,8 +199,10 @@
   void Free();
   CapsuleType capsule_type_;
   union {
+    DatagramCapsule datagram_capsule_;
     LegacyDatagramCapsule legacy_datagram_capsule_;
-    DatagramWithoutContextCapsule datagram_without_context_capsule_;
+    LegacyDatagramWithoutContextCapsule
+        legacy_datagram_without_context_capsule_;
     CloseWebTransportSessionCapsule close_web_transport_session_capsule_;
     AddressRequestCapsule* address_request_capsule_;
     AddressAssignCapsule* address_assign_capsule_;
diff --git a/quiche/quic/core/http/capsule_test.cc b/quiche/quic/core/http/capsule_test.cc
index a686095..95869c6 100644
--- a/quiche/quic/core/http/capsule_test.cc
+++ b/quiche/quic/core/http/capsule_test.cc
@@ -68,6 +68,22 @@
   CapsuleParser capsule_parser_;
 };
 
+TEST_F(CapsuleTest, DatagramCapsule) {
+  std::string capsule_fragment = absl::HexStringToBytes(
+      "00"                // DATAGRAM capsule type
+      "08"                // capsule length
+      "a1a2a3a4a5a6a7a8"  // HTTP Datagram payload
+  );
+  std::string datagram_payload = absl::HexStringToBytes("a1a2a3a4a5a6a7a8");
+  Capsule expected_capsule = Capsule::Datagram(datagram_payload);
+  {
+    EXPECT_CALL(visitor_, OnCapsule(expected_capsule));
+    ASSERT_TRUE(capsule_parser_.IngestCapsuleFragment(capsule_fragment));
+  }
+  ValidateParserIsEmpty();
+  TestSerialization(expected_capsule, capsule_fragment);
+}
+
 TEST_F(CapsuleTest, LegacyDatagramCapsule) {
   std::string capsule_fragment = absl::HexStringToBytes(
       "80ff37a0"          // LEGACY_DATAGRAM capsule type
@@ -84,14 +100,15 @@
   TestSerialization(expected_capsule, capsule_fragment);
 }
 
-TEST_F(CapsuleTest, DatagramWithoutContextCapsule) {
+TEST_F(CapsuleTest, LegacyDatagramWithoutContextCapsule) {
   std::string capsule_fragment = absl::HexStringToBytes(
-      "80ff37a5"          // DATAGRAM_WITHOUT_CONTEXT capsule type
+      "80ff37a5"          // LEGACY_DATAGRAM_WITHOUT_CONTEXT capsule type
       "08"                // capsule length
       "a1a2a3a4a5a6a7a8"  // HTTP Datagram payload
   );
   std::string datagram_payload = absl::HexStringToBytes("a1a2a3a4a5a6a7a8");
-  Capsule expected_capsule = Capsule::DatagramWithoutContext(datagram_payload);
+  Capsule expected_capsule =
+      Capsule::LegacyDatagramWithoutContext(datagram_payload);
   {
     EXPECT_CALL(visitor_, OnCapsule(expected_capsule));
     ASSERT_TRUE(capsule_parser_.IngestCapsuleFragment(capsule_fragment));
@@ -236,12 +253,12 @@
 
 TEST_F(CapsuleTest, UnknownCapsule) {
   std::string capsule_fragment = absl::HexStringToBytes(
-      "33"                // unknown capsule type of 0x33
+      "17"                // unknown capsule type of 0x17
       "08"                // capsule length
       "a1a2a3a4a5a6a7a8"  // unknown capsule data
   );
   std::string unknown_capsule_data = absl::HexStringToBytes("a1a2a3a4a5a6a7a8");
-  Capsule expected_capsule = Capsule::Unknown(0x33, unknown_capsule_data);
+  Capsule expected_capsule = Capsule::Unknown(0x17, unknown_capsule_data);
   {
     EXPECT_CALL(visitor_, OnCapsule(expected_capsule));
     ASSERT_TRUE(capsule_parser_.IngestCapsuleFragment(capsule_fragment));
@@ -252,19 +269,17 @@
 
 TEST_F(CapsuleTest, TwoCapsules) {
   std::string capsule_fragment = absl::HexStringToBytes(
-      "80ff37a5"          // DATAGRAM_WITHOUT_CONTEXT capsule type
+      "00"                // DATAGRAM capsule type
       "08"                // capsule length
       "a1a2a3a4a5a6a7a8"  // HTTP Datagram payload
-      "80ff37a5"          // DATAGRAM_WITHOUT_CONTEXT capsule type
+      "00"                // DATAGRAM capsule type
       "08"                // capsule length
       "b1b2b3b4b5b6b7b8"  // HTTP Datagram payload
   );
   std::string datagram_payload1 = absl::HexStringToBytes("a1a2a3a4a5a6a7a8");
   std::string datagram_payload2 = absl::HexStringToBytes("b1b2b3b4b5b6b7b8");
-  Capsule expected_capsule1 =
-      Capsule::DatagramWithoutContext(datagram_payload1);
-  Capsule expected_capsule2 =
-      Capsule::DatagramWithoutContext(datagram_payload2);
+  Capsule expected_capsule1 = Capsule::Datagram(datagram_payload1);
+  Capsule expected_capsule2 = Capsule::Datagram(datagram_payload2);
   {
     InSequence s;
     EXPECT_CALL(visitor_, OnCapsule(expected_capsule1));
@@ -276,13 +291,13 @@
 
 TEST_F(CapsuleTest, TwoCapsulesPartialReads) {
   std::string capsule_fragment1 = absl::HexStringToBytes(
-      "80ff37a5"  // first capsule DATAGRAM_WITHOUT_CONTEXT capsule type
-      "08"        // frist capsule length
+      "00"        // first capsule DATAGRAM capsule type
+      "08"        // first capsule length
       "a1a2a3a4"  // first half of HTTP Datagram payload of first capsule
   );
   std::string capsule_fragment2 = absl::HexStringToBytes(
       "a5a6a7a8"  // second half of HTTP Datagram payload 1
-      "80ff37a5"  // second capsule DATAGRAM_WITHOUT_CONTEXT capsule type
+      "00"        // second capsule DATAGRAM capsule type
   );
   std::string capsule_fragment3 = absl::HexStringToBytes(
       "08"                // second capsule length
@@ -291,10 +306,8 @@
   capsule_parser_.ErrorIfThereIsRemainingBufferedData();
   std::string datagram_payload1 = absl::HexStringToBytes("a1a2a3a4a5a6a7a8");
   std::string datagram_payload2 = absl::HexStringToBytes("b1b2b3b4b5b6b7b8");
-  Capsule expected_capsule1 =
-      Capsule::DatagramWithoutContext(datagram_payload1);
-  Capsule expected_capsule2 =
-      Capsule::DatagramWithoutContext(datagram_payload2);
+  Capsule expected_capsule1 = Capsule::Datagram(datagram_payload1);
+  Capsule expected_capsule2 = Capsule::Datagram(datagram_payload2);
   {
     InSequence s;
     EXPECT_CALL(visitor_, OnCapsule(expected_capsule1));
@@ -308,19 +321,17 @@
 
 TEST_F(CapsuleTest, TwoCapsulesOneByteAtATime) {
   std::string capsule_fragment = absl::HexStringToBytes(
-      "80ff37a5"          // DATAGRAM_WITHOUT_CONTEXT capsule type
+      "00"                // DATAGRAM capsule type
       "08"                // capsule length
       "a1a2a3a4a5a6a7a8"  // HTTP Datagram payload
-      "80ff37a5"          // DATAGRAM_WITHOUT_CONTEXT capsule type
+      "00"                // DATAGRAM capsule type
       "08"                // capsule length
       "b1b2b3b4b5b6b7b8"  // HTTP Datagram payload
   );
   std::string datagram_payload1 = absl::HexStringToBytes("a1a2a3a4a5a6a7a8");
   std::string datagram_payload2 = absl::HexStringToBytes("b1b2b3b4b5b6b7b8");
-  Capsule expected_capsule1 =
-      Capsule::DatagramWithoutContext(datagram_payload1);
-  Capsule expected_capsule2 =
-      Capsule::DatagramWithoutContext(datagram_payload2);
+  Capsule expected_capsule1 = Capsule::Datagram(datagram_payload1);
+  Capsule expected_capsule2 = Capsule::Datagram(datagram_payload2);
   for (size_t i = 0; i < capsule_fragment.size(); i++) {
     if (i < capsule_fragment.size() / 2 - 1) {
       EXPECT_CALL(visitor_, OnCapsule(_)).Times(0);
@@ -348,7 +359,7 @@
 
 TEST_F(CapsuleTest, PartialCapsuleThenError) {
   std::string capsule_fragment = absl::HexStringToBytes(
-      "80ff37a5"  // DATAGRAM_WITHOUT_CONTEXT capsule type
+      "00"        // DATAGRAM capsule type
       "08"        // capsule length
       "a1a2a3a4"  // first half of HTTP Datagram payload
   );
@@ -367,7 +378,7 @@
 
 TEST_F(CapsuleTest, RejectOverlyLongCapsule) {
   std::string capsule_fragment = absl::HexStringToBytes(
-                                     "33"        // unknown capsule type of 0x33
+                                     "17"        // unknown capsule type of 0x17
                                      "80123456"  // capsule length
                                      ) +
                                  std::string(1111111, '?');
diff --git a/quiche/quic/core/http/http_constants.cc b/quiche/quic/core/http/http_constants.cc
index e429678..e585535 100644
--- a/quiche/quic/core/http/http_constants.cc
+++ b/quiche/quic/core/http/http_constants.cc
@@ -18,7 +18,7 @@
     RETURN_STRING_LITERAL(SETTINGS_MAX_FIELD_SECTION_SIZE);
     RETURN_STRING_LITERAL(SETTINGS_QPACK_BLOCKED_STREAMS);
     RETURN_STRING_LITERAL(SETTINGS_H3_DATAGRAM_DRAFT04);
-    RETURN_STRING_LITERAL(SETTINGS_H3_DATAGRAM_DRAFT09);
+    RETURN_STRING_LITERAL(SETTINGS_H3_DATAGRAM);
     RETURN_STRING_LITERAL(SETTINGS_WEBTRANS_DRAFT00);
     RETURN_STRING_LITERAL(SETTINGS_ENABLE_CONNECT_PROTOCOL);
     RETURN_STRING_LITERAL(SETTINGS_ENABLE_METADATA);
diff --git a/quiche/quic/core/http/http_constants.h b/quiche/quic/core/http/http_constants.h
index b5dc19b..feec521 100644
--- a/quiche/quic/core/http/http_constants.h
+++ b/quiche/quic/core/http/http_constants.h
@@ -40,8 +40,8 @@
   SETTINGS_QPACK_BLOCKED_STREAMS = 0x07,
   // draft-ietf-masque-h3-datagram-04.
   SETTINGS_H3_DATAGRAM_DRAFT04 = 0xffd277,
-  // draft-ietf-masque-h3-datagram-09.
-  SETTINGS_H3_DATAGRAM_DRAFT09 = 0x33,
+  // RFC 9297.
+  SETTINGS_H3_DATAGRAM = 0x33,
   // draft-ietf-webtrans-http3-00
   SETTINGS_WEBTRANS_DRAFT00 = 0x2b603742,
   // draft-ietf-httpbis-h3-websockets
diff --git a/quiche/quic/core/http/quic_spdy_session.cc b/quiche/quic/core/http/quic_spdy_session.cc
index 8b6d5ea..c9a0c1e 100644
--- a/quiche/quic/core/http/quic_spdy_session.cc
+++ b/quiche/quic/core/http/quic_spdy_session.cc
@@ -530,12 +530,12 @@
       case HttpDatagramSupport::kDraft04:
         settings_.values[SETTINGS_H3_DATAGRAM_DRAFT04] = 1;
         break;
-      case HttpDatagramSupport::kDraft09:
-        settings_.values[SETTINGS_H3_DATAGRAM_DRAFT09] = 1;
+      case HttpDatagramSupport::kRfc:
+        settings_.values[SETTINGS_H3_DATAGRAM] = 1;
         break;
-      case HttpDatagramSupport::kDraft04And09:
+      case HttpDatagramSupport::kRfcAndDraft04:
+        settings_.values[SETTINGS_H3_DATAGRAM] = 1;
         settings_.values[SETTINGS_H3_DATAGRAM_DRAFT04] = 1;
-        settings_.values[SETTINGS_H3_DATAGRAM_DRAFT09] = 1;
         break;
     }
   }
@@ -1157,7 +1157,8 @@
         HttpDatagramSupport local_http_datagram_support =
             LocalHttpDatagramSupport();
         if (local_http_datagram_support != HttpDatagramSupport::kDraft04 &&
-            local_http_datagram_support != HttpDatagramSupport::kDraft04And09) {
+            local_http_datagram_support !=
+                HttpDatagramSupport::kRfcAndDraft04) {
           break;
         }
         QUIC_DVLOG(1) << ENDPOINT
@@ -1169,17 +1170,20 @@
         if (!VerifySettingIsZeroOrOne(id, value)) {
           return false;
         }
-        if (value && http_datagram_support_ != HttpDatagramSupport::kDraft09) {
-          // If both draft-04 and draft-09 are supported, use draft-09.
+        if (value && http_datagram_support_ != HttpDatagramSupport::kRfc) {
+          // If both RFC 9297 and draft-04 are supported, we use the RFC. This
+          // is implemented by ignoring SETTINGS_H3_DATAGRAM_DRAFT04 when we've
+          // already parsed SETTINGS_H3_DATAGRAM.
           http_datagram_support_ = HttpDatagramSupport::kDraft04;
         }
         break;
       }
-      case SETTINGS_H3_DATAGRAM_DRAFT09: {
+      case SETTINGS_H3_DATAGRAM: {
         HttpDatagramSupport local_http_datagram_support =
             LocalHttpDatagramSupport();
-        if (local_http_datagram_support != HttpDatagramSupport::kDraft09 &&
-            local_http_datagram_support != HttpDatagramSupport::kDraft04And09) {
+        if (local_http_datagram_support != HttpDatagramSupport::kRfc &&
+            local_http_datagram_support !=
+                HttpDatagramSupport::kRfcAndDraft04) {
           break;
         }
         QUIC_DVLOG(1) << ENDPOINT
@@ -1192,7 +1196,7 @@
           return false;
         }
         if (value) {
-          http_datagram_support_ = HttpDatagramSupport::kDraft09;
+          http_datagram_support_ = HttpDatagramSupport::kRfc;
         }
         break;
       }
@@ -1830,9 +1834,9 @@
       return "None";
     case HttpDatagramSupport::kDraft04:
       return "Draft04";
-    case HttpDatagramSupport::kDraft09:
+    case HttpDatagramSupport::kRfc:
       return "Draft09";
-    case HttpDatagramSupport::kDraft04And09:
+    case HttpDatagramSupport::kRfcAndDraft04:
       return "Draft04And09";
   }
   return absl::StrCat("Unknown(", static_cast<int>(http_datagram_support), ")");
diff --git a/quiche/quic/core/http/quic_spdy_session.h b/quiche/quic/core/http/quic_spdy_session.h
index 5c779c5..0cfb629 100644
--- a/quiche/quic/core/http/quic_spdy_session.h
+++ b/quiche/quic/core/http/quic_spdy_session.h
@@ -116,13 +116,14 @@
   virtual void OnSettingsFrameResumed(const SettingsFrame& /*frame*/) {}
 };
 
-// Whether draft-ietf-masque-h3-datagram is supported on this session and if so
-// which draft is currently in use.
+// Whether HTTP Datagrams are supported on this session and if so which version
+// is currently in use.
 enum class HttpDatagramSupport : uint8_t {
   kNone,  // HTTP Datagrams are not supported for this session.
   kDraft04,
-  kDraft09,
-  kDraft04And09,  // Only used locally for sending, we only negotiate one draft.
+  kRfc,
+  kRfcAndDraft04,  // Only used locally for sending, we only negotiate one
+                   // version.
 };
 
 QUIC_EXPORT_PRIVATE std::string HttpDatagramSupportToString(
diff --git a/quiche/quic/core/http/quic_spdy_session_test.cc b/quiche/quic/core/http/quic_spdy_session_test.cc
index fcc6103..7897570 100644
--- a/quiche/quic/core/http/quic_spdy_session_test.cc
+++ b/quiche/quic/core/http/quic_spdy_session_test.cc
@@ -3370,12 +3370,12 @@
     case HttpDatagramSupport::kDraft04:
       settings.values[SETTINGS_H3_DATAGRAM_DRAFT04] = 1;
       break;
-    case HttpDatagramSupport::kDraft09:
-      settings.values[SETTINGS_H3_DATAGRAM_DRAFT09] = 1;
+    case HttpDatagramSupport::kRfc:
+      settings.values[SETTINGS_H3_DATAGRAM] = 1;
       break;
-    case HttpDatagramSupport::kDraft04And09:
+    case HttpDatagramSupport::kRfcAndDraft04:
+      settings.values[SETTINGS_H3_DATAGRAM] = 1;
       settings.values[SETTINGS_H3_DATAGRAM_DRAFT04] = 1;
-      settings.values[SETTINGS_H3_DATAGRAM_DRAFT09] = 1;
       break;
   }
   std::string data = std::string(1, kControlStream) +
@@ -3403,7 +3403,7 @@
 TEST_P(QuicSpdySessionTestClient, HttpDatagramSettingLocal04Remote09) {
   TestHttpDatagramSetting(
       /*local_support=*/HttpDatagramSupport::kDraft04,
-      /*remote_support=*/HttpDatagramSupport::kDraft09,
+      /*remote_support=*/HttpDatagramSupport::kRfc,
       /*expected_support=*/HttpDatagramSupport::kNone,
       /*expected_datagram_supported=*/false);
 }
@@ -3411,14 +3411,14 @@
 TEST_P(QuicSpdySessionTestClient, HttpDatagramSettingLocal04Remote04And09) {
   TestHttpDatagramSetting(
       /*local_support=*/HttpDatagramSupport::kDraft04,
-      /*remote_support=*/HttpDatagramSupport::kDraft04And09,
+      /*remote_support=*/HttpDatagramSupport::kRfcAndDraft04,
       /*expected_support=*/HttpDatagramSupport::kDraft04,
       /*expected_datagram_supported=*/true);
 }
 
 TEST_P(QuicSpdySessionTestClient, HttpDatagramSettingLocal09Remote04) {
   TestHttpDatagramSetting(
-      /*local_support=*/HttpDatagramSupport::kDraft09,
+      /*local_support=*/HttpDatagramSupport::kRfc,
       /*remote_support=*/HttpDatagramSupport::kDraft04,
       /*expected_support=*/HttpDatagramSupport::kNone,
       /*expected_datagram_supported=*/false);
@@ -3426,23 +3426,23 @@
 
 TEST_P(QuicSpdySessionTestClient, HttpDatagramSettingLocal09Remote09) {
   TestHttpDatagramSetting(
-      /*local_support=*/HttpDatagramSupport::kDraft09,
-      /*remote_support=*/HttpDatagramSupport::kDraft09,
-      /*expected_support=*/HttpDatagramSupport::kDraft09,
+      /*local_support=*/HttpDatagramSupport::kRfc,
+      /*remote_support=*/HttpDatagramSupport::kRfc,
+      /*expected_support=*/HttpDatagramSupport::kRfc,
       /*expected_datagram_supported=*/true);
 }
 
 TEST_P(QuicSpdySessionTestClient, HttpDatagramSettingLocal09Remote04And09) {
   TestHttpDatagramSetting(
-      /*local_support=*/HttpDatagramSupport::kDraft09,
-      /*remote_support=*/HttpDatagramSupport::kDraft04And09,
-      /*expected_support=*/HttpDatagramSupport::kDraft09,
+      /*local_support=*/HttpDatagramSupport::kRfc,
+      /*remote_support=*/HttpDatagramSupport::kRfcAndDraft04,
+      /*expected_support=*/HttpDatagramSupport::kRfc,
       /*expected_datagram_supported=*/true);
 }
 
 TEST_P(QuicSpdySessionTestClient, HttpDatagramSettingLocal04And09Remote04) {
   TestHttpDatagramSetting(
-      /*local_support=*/HttpDatagramSupport::kDraft04And09,
+      /*local_support=*/HttpDatagramSupport::kRfcAndDraft04,
       /*remote_support=*/HttpDatagramSupport::kDraft04,
       /*expected_support=*/HttpDatagramSupport::kDraft04,
       /*expected_datagram_supported=*/true);
@@ -3450,18 +3450,18 @@
 
 TEST_P(QuicSpdySessionTestClient, HttpDatagramSettingLocal04And09Remote09) {
   TestHttpDatagramSetting(
-      /*local_support=*/HttpDatagramSupport::kDraft04And09,
-      /*remote_support=*/HttpDatagramSupport::kDraft09,
-      /*expected_support=*/HttpDatagramSupport::kDraft09,
+      /*local_support=*/HttpDatagramSupport::kRfcAndDraft04,
+      /*remote_support=*/HttpDatagramSupport::kRfc,
+      /*expected_support=*/HttpDatagramSupport::kRfc,
       /*expected_datagram_supported=*/true);
 }
 
 TEST_P(QuicSpdySessionTestClient,
        HttpDatagramSettingLocal04And09Remote04And09) {
   TestHttpDatagramSetting(
-      /*local_support=*/HttpDatagramSupport::kDraft04And09,
-      /*remote_support=*/HttpDatagramSupport::kDraft04And09,
-      /*expected_support=*/HttpDatagramSupport::kDraft09,
+      /*local_support=*/HttpDatagramSupport::kRfcAndDraft04,
+      /*remote_support=*/HttpDatagramSupport::kRfcAndDraft04,
+      /*expected_support=*/HttpDatagramSupport::kRfc,
       /*expected_datagram_supported=*/true);
 }
 TEST_P(QuicSpdySessionTestClient, WebTransportSetting) {
diff --git a/quiche/quic/core/http/quic_spdy_stream.cc b/quiche/quic/core/http/quic_spdy_stream.cc
index 2584a39..ee1e685 100644
--- a/quiche/quic/core/http/quic_spdy_stream.cc
+++ b/quiche/quic/core/http/quic_spdy_stream.cc
@@ -1370,13 +1370,16 @@
     return false;
   }
   switch (capsule.capsule_type()) {
+    case CapsuleType::DATAGRAM: {
+      HandleReceivedDatagram(capsule.datagram_capsule().http_datagram_payload);
+    } break;
     case CapsuleType::LEGACY_DATAGRAM: {
       HandleReceivedDatagram(
           capsule.legacy_datagram_capsule().http_datagram_payload);
     } break;
-    case CapsuleType::DATAGRAM_WITHOUT_CONTEXT: {
-      HandleReceivedDatagram(
-          capsule.datagram_without_context_capsule().http_datagram_payload);
+    case CapsuleType::LEGACY_DATAGRAM_WITHOUT_CONTEXT: {
+      HandleReceivedDatagram(capsule.legacy_datagram_without_context_capsule()
+                                 .http_datagram_payload);
     } break;
     case CapsuleType::CLOSE_WEBTRANSPORT_SESSION: {
       if (web_transport_ == nullptr) {
@@ -1541,12 +1544,12 @@
   QuicByteCount prefix_size = 0;
   switch (spdy_session_->http_datagram_support()) {
     case HttpDatagramSupport::kDraft04:
-    case HttpDatagramSupport::kDraft09:
+    case HttpDatagramSupport::kRfc:
       prefix_size =
           QuicDataWriter::GetVarInt62Len(id() / kHttpDatagramStreamIdDivisor);
       break;
     case HttpDatagramSupport::kNone:
-    case HttpDatagramSupport::kDraft04And09:
+    case HttpDatagramSupport::kRfcAndDraft04:
       QUIC_BUG(GetMaxDatagramSize called with no datagram support)
           << "GetMaxDatagramSize() called when no HTTP/3 datagram support has "
              "been negotiated.  Support value: "
diff --git a/quiche/quic/core/http/quic_spdy_stream_test.cc b/quiche/quic/core/http/quic_spdy_stream_test.cc
index 960060e..81f6d0a 100644
--- a/quiche/quic/core/http/quic_spdy_stream_test.cc
+++ b/quiche/quic/core/http/quic_spdy_stream_test.cc
@@ -3078,18 +3078,18 @@
   EXPECT_FALSE(stream_->write_side_closed());
 }
 
-TEST_P(QuicSpdyStreamTest, ProcessOutgoingWebTransportHeadersDatagramDraft04) {
+TEST_P(QuicSpdyStreamTest, ProcessOutgoingWebTransportHeaders) {
   if (!UsesHttp3()) {
     return;
   }
 
   InitializeWithPerspective(kShouldProcessData, Perspective::IS_CLIENT);
-  session_->set_local_http_datagram_support(HttpDatagramSupport::kDraft04);
+  session_->set_local_http_datagram_support(HttpDatagramSupport::kRfc);
   session_->EnableWebTransport();
   session_->OnSetting(SETTINGS_ENABLE_CONNECT_PROTOCOL, 1);
   QuicSpdySessionPeer::EnableWebTransport(session_.get());
   QuicSpdySessionPeer::SetHttpDatagramSupport(session_.get(),
-                                              HttpDatagramSupport::kDraft04);
+                                              HttpDatagramSupport::kRfc);
 
   EXPECT_CALL(*stream_, WriteHeadersMock(false));
   EXPECT_CALL(*session_, WritevData(stream_->id(), _, _, _, _, _))
@@ -3103,17 +3103,17 @@
   EXPECT_EQ(stream_->id(), stream_->web_transport()->id());
 }
 
-TEST_P(QuicSpdyStreamTest, ProcessIncomingWebTransportHeadersDatagramDraft04) {
+TEST_P(QuicSpdyStreamTest, ProcessIncomingWebTransportHeaders) {
   if (!UsesHttp3()) {
     return;
   }
 
   Initialize(kShouldProcessData);
-  session_->set_local_http_datagram_support(HttpDatagramSupport::kDraft04);
+  session_->set_local_http_datagram_support(HttpDatagramSupport::kRfc);
   session_->EnableWebTransport();
   QuicSpdySessionPeer::EnableWebTransport(session_.get());
   QuicSpdySessionPeer::SetHttpDatagramSupport(session_.get(),
-                                              HttpDatagramSupport::kDraft04);
+                                              HttpDatagramSupport::kRfc);
 
   headers_[":method"] = "CONNECT";
   headers_[":protocol"] = "webtransport";
@@ -3134,9 +3134,9 @@
     return;
   }
   InitializeWithPerspective(kShouldProcessData, Perspective::IS_CLIENT);
-  session_->set_local_http_datagram_support(HttpDatagramSupport::kDraft09);
+  session_->set_local_http_datagram_support(HttpDatagramSupport::kRfc);
   QuicSpdySessionPeer::SetHttpDatagramSupport(session_.get(),
-                                              HttpDatagramSupport::kDraft09);
+                                              HttpDatagramSupport::kRfc);
   headers_[":method"] = "CONNECT";
   headers_[":protocol"] = "webtransport";
   ProcessHeaders(false, headers_);
@@ -3174,9 +3174,9 @@
     return;
   }
   Initialize(kShouldProcessData);
-  session_->set_local_http_datagram_support(HttpDatagramSupport::kDraft09);
+  session_->set_local_http_datagram_support(HttpDatagramSupport::kRfc);
   QuicSpdySessionPeer::SetHttpDatagramSupport(session_.get(),
-                                              HttpDatagramSupport::kDraft09);
+                                              HttpDatagramSupport::kRfc);
   std::string http_datagram_payload = {1, 2, 3, 4, 5, 6};
   EXPECT_CALL(*connection_, SendMessage(1, _, false))
       .WillOnce(Return(MESSAGE_STATUS_SUCCESS));
@@ -3189,9 +3189,9 @@
     return;
   }
   Initialize(kShouldProcessData);
-  session_->set_local_http_datagram_support(HttpDatagramSupport::kDraft09);
+  session_->set_local_http_datagram_support(HttpDatagramSupport::kRfc);
   QuicSpdySessionPeer::SetHttpDatagramSupport(session_.get(),
-                                              HttpDatagramSupport::kDraft09);
+                                              HttpDatagramSupport::kRfc);
   EXPECT_GT(stream_->GetMaxDatagramSize(), 512u);
 }
 
@@ -3200,9 +3200,9 @@
     return;
   }
   Initialize(kShouldProcessData);
-  session_->set_local_http_datagram_support(HttpDatagramSupport::kDraft09);
+  session_->set_local_http_datagram_support(HttpDatagramSupport::kRfc);
   QuicSpdySessionPeer::SetHttpDatagramSupport(session_.get(),
-                                              HttpDatagramSupport::kDraft09);
+                                              HttpDatagramSupport::kRfc);
   SavingHttp3DatagramVisitor h3_datagram_visitor;
   stream_->RegisterHttp3DatagramVisitor(&h3_datagram_visitor);
   SavingConnectIpVisitor connect_ip_visitor;
@@ -3212,7 +3212,7 @@
   ProcessHeaders(/*fin=*/false, headers_);
   // Datagram capsule.
   std::string http_datagram_payload = {1, 2, 3, 4, 5, 6};
-  stream_->OnCapsule(Capsule::DatagramWithoutContext(http_datagram_payload));
+  stream_->OnCapsule(Capsule::Datagram(http_datagram_payload));
   EXPECT_THAT(h3_datagram_visitor.received_h3_datagrams(),
               ElementsAre(SavingHttp3DatagramVisitor::SavedHttp3Datagram{
                   stream_->id(), http_datagram_payload}));
diff --git a/quiche/quic/masque/masque_client_session.h b/quiche/quic/masque/masque_client_session.h
index 66c7e2e..43609dc 100644
--- a/quiche/quic/masque/masque_client_session.h
+++ b/quiche/quic/masque/masque_client_session.h
@@ -125,7 +125,7 @@
   };
 
   HttpDatagramSupport LocalHttpDatagramSupport() override {
-    return HttpDatagramSupport::kDraft09;
+    return HttpDatagramSupport::kRfc;
   }
 
   const ConnectUdpClientState* GetOrCreateConnectUdpClientState(
diff --git a/quiche/quic/masque/masque_server_session.h b/quiche/quic/masque/masque_server_session.h
index 20b85a1..f26ef4f 100644
--- a/quiche/quic/masque/masque_server_session.h
+++ b/quiche/quic/masque/masque_server_session.h
@@ -93,7 +93,7 @@
   // From QuicSpdySession.
   bool OnSettingsFrame(const SettingsFrame& frame) override;
   HttpDatagramSupport LocalHttpDatagramSupport() override {
-    return HttpDatagramSupport::kDraft09;
+    return HttpDatagramSupport::kRfc;
   }
 
   MasqueServerBackend* masque_server_backend_;  // Unowned.