diff --git a/internal/protocol/params.go b/internal/protocol/params.go
index a124f3aa..cafcdcae 100644
--- a/internal/protocol/params.go
+++ b/internal/protocol/params.go
@@ -125,6 +125,11 @@ const MaxPostHandshakeCryptoFrameSize = 1000
 // but must ensure that a maximum size ACK frame fits into one packet.
 const MaxAckFrameSize ByteCount = 1000
 
+// MaxDatagramFrameSize is the maximum size of a DATAGRAM frame as defined in
+// https://datatracker.ietf.org/doc/draft-pauly-quic-datagram/.
+// The size is chosen such that a DATAGRAM frame fits into a QUIC packet.
+const MaxDatagramFrameSize ByteCount = 1200
+
 // MaxNumAckRanges is the maximum number of ACK ranges that we send in an ACK frame.
 // It also serves as a limit for the packet history.
 // If at any point we keep track of more ranges, old ranges are discarded.
diff --git a/session.go b/session.go
index 761e91ad..4243f34e 100644
--- a/session.go
+++ b/session.go
@@ -296,7 +296,9 @@ var newSession = func(
 		ActiveConnectionIDLimit:         protocol.MaxActiveConnectionIDs,
 		InitialSourceConnectionID:       srcConnID,
 		RetrySourceConnectionID:         retrySrcConnID,
-		MaxDatagramFrameSize:            protocol.InvalidByteCount, // disable DATAGRAMs
+	}
+	if s.config.EnableDatagrams {
+		params.MaxDatagramFrameSize = protocol.MaxDatagramFrameSize
 	}
 	if s.tracer != nil {
 		s.tracer.SentTransportParameters(params)
@@ -417,7 +419,9 @@ var newClientSession = func(
 		DisableActiveMigration:         true,
 		ActiveConnectionIDLimit:        protocol.MaxActiveConnectionIDs,
 		InitialSourceConnectionID:      srcConnID,
-		MaxDatagramFrameSize:           protocol.InvalidByteCount, // disable DATAGRAMs
+	}
+	if s.config.EnableDatagrams {
+		params.MaxDatagramFrameSize = protocol.MaxDatagramFrameSize
 	}
 	if s.tracer != nil {
 		s.tracer.SentTransportParameters(params)