diff --git a/listeners.go b/listeners.go
index 6031f98e495..4d4a400b2e2 100644
--- a/listeners.go
+++ b/listeners.go
@@ -480,8 +480,9 @@ func (na NetworkAddress) ListenQUIC(ctx context.Context, portOffset uint, config
 		earlyLn, err := tr.ListenEarly(
 			http3.ConfigureTLSConfig(quicTlsConfig),
 			&quic.Config{
-				Allow0RTT: allow0rtt,
-				Tracer:    h3qlog.DefaultConnectionTracer,
+				InitialPacketSize: 1200,
+				Allow0RTT:         allow0rtt,
+				Tracer:            h3qlog.DefaultConnectionTracer,
 			},
 		)
 		if err != nil {
diff --git a/modules/caddyhttp/server.go b/modules/caddyhttp/server.go
index 391a0f41a44..2dc7506c614 100644
--- a/modules/caddyhttp/server.go
+++ b/modules/caddyhttp/server.go
@@ -825,8 +825,9 @@ func (s *Server) serveHTTP3(addr caddy.NetworkAddress, tlsCfg *tls.Config) error
 			TLSConfig:      tlsCfg,
 			MaxHeaderBytes: s.MaxHeaderBytes,
 			QUICConfig: &quic.Config{
-				Versions: []quic.Version{quic.Version1, quic.Version2},
-				Tracer:   h3qlog.DefaultConnectionTracer,
+				Versions:          []quic.Version{quic.Version1, quic.Version2},
+				InitialPacketSize: 1200,
+				Tracer:            h3qlog.DefaultConnectionTracer,
 			},
 			IdleTimeout: time.Duration(s.IdleTimeout),
 		}