diff --git a/multiaddr_test.go b/multiaddr_test.go
index ee6ecf2..0f4445b 100644
--- a/multiaddr_test.go
+++ b/multiaddr_test.go
@@ -157,6 +157,7 @@ func TestConstructSucceeds(t *testing.T) {
 		"/ip4/127.0.0.1/tcp/1234",
 		"/ip4/127.0.0.1/tcp/1234/",
 		"/ip4/127.0.0.1/udp/1234/quic",
+		"/ip4/127.0.0.1/udp/1234/quic/webtransport",
 		"/ip4/127.0.0.1/ipfs/QmcgpsyWgH8Y8ajJz1Cu72KnS5uo2Aa2LpzU7kinSupNKC",
 		"/ip4/127.0.0.1/ipfs/QmcgpsyWgH8Y8ajJz1Cu72KnS5uo2Aa2LpzU7kinSupNKC/tcp/1234",
 		"/ip4/127.0.0.1/ipfs/k2k4r8oqamigqdo6o7hsbfwd45y70oyynp98usk7zmyfrzpqxh1pohl7",
diff --git a/protocols.go b/protocols.go
index 5895894..9f6cd64 100644
--- a/protocols.go
+++ b/protocols.go
@@ -15,6 +15,7 @@ const (
 	P_IP6ZONE           = 0x002A
 	P_IPCIDR            = 0x002B
 	P_QUIC              = 0x01CC
+	P_WEBTRANSPORT      = 0x01D1
 	P_SCTP              = 0x0084
 	P_CIRCUIT           = 0x0122
 	P_UDT               = 0x012D
@@ -178,6 +179,11 @@ var (
 		Code:  P_QUIC,
 		VCode: CodeToVarint(P_QUIC),
 	}
+	protoWEBTRANSPORT = Protocol{
+		Name:  "webtransport",
+		Code:  P_WEBTRANSPORT,
+		VCode: CodeToVarint(P_WEBTRANSPORT),
+	}
 	protoHTTP = Protocol{
 		Name:  "http",
 		Code:  P_HTTP,
@@ -257,6 +263,7 @@ func init() {
 		protoUTP,
 		protoUDT,
 		protoQUIC,
+		protoWEBTRANSPORT,
 		protoHTTP,
 		protoHTTPS,
 		protoP2P,