diff --git a/.changeset/sip-carrier-outbound.md b/.changeset/sip-carrier-outbound.md
new file mode 100644
index 000000000..cdc6e2140
--- /dev/null
+++ b/.changeset/sip-carrier-outbound.md
@@ -0,0 +1,5 @@
+---
+"github.com/livekit/protocol": patch
+---
+
+Relax SIP outbound validation to support carriers.
diff --git a/livekit/sip.go b/livekit/sip.go
index 03af80063..f8b41e0e7 100644
--- a/livekit/sip.go
+++ b/livekit/sip.go
@@ -764,8 +764,8 @@ func (p *UpdateSIPDispatchRuleRequest_Update) Apply(info *SIPDispatchRuleInfo) (
 }
 
 func (p *CreateSIPParticipantRequest) Validate() error {
-	if p.SipTrunkId == "" && p.Trunk == nil {
-		return errors.New("missing sip trunk id")
+	if p.SipTrunkId == "" && p.Trunk == nil && p.SipNumber == "" {
+		return errors.New("missing sip trunk id and sip number")
 	}
 	if p.Trunk != nil {
 		if err := p.Trunk.Validate(); err != nil {