diff --git a/quic/core/quic_flags_list.h b/quic/core/quic_flags_list.h
index e515a96..ecfa7c3 100644
--- a/quic/core/quic_flags_list.h
+++ b/quic/core/quic_flags_list.h
@@ -13,7 +13,7 @@
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_allow_client_enabled_bbr_v2, false)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_bbr2_avoid_too_low_probe_bw_cwnd, false)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_bbr2_bw_startup, true)
-QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_bbr2_disable_reno_coexistence, false)
+QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_bbr2_disable_reno_coexistence, true)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_bbr2_fewer_startup_round_trips, false)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_bbr2_reset_max_bytes_delivered, false)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_bbr2_use_bytes_delivered, true)