diff --git a/livekit-api/livekit/api/sip_service.py b/livekit-api/livekit/api/sip_service.py
index 7cf67d23..c222cdf0 100644
--- a/livekit-api/livekit/api/sip_service.py
+++ b/livekit-api/livekit/api/sip_service.py
@@ -49,9 +49,10 @@
 
 
 def _as_sip_error(err: ServerError) -> ServerError:
-    """Surface a SIP dialing failure as a SipCallError so callers can branch on
-    the SIP status; other failures (auth, validation) are returned unchanged."""
-    if "sip_status_code" in err.metadata:
+    """Surface a SIP dialing or transfer failure as a SipCallError so callers can
+    branch on the SIP status or the transfer reason; other failures (auth,
+    validation) are returned unchanged."""
+    if "sip_status_code" in err.metadata or "sip_transfer_reason" in err.metadata:
         return SipCallError.from_server_error(err)
     return err
 
diff --git a/livekit-api/livekit/api/twirp_client.py b/livekit-api/livekit/api/twirp_client.py
index 228c6d1d..efd5ffde 100644
--- a/livekit-api/livekit/api/twirp_client.py
+++ b/livekit-api/livekit/api/twirp_client.py
@@ -87,10 +87,20 @@ def __str__(self) -> str:
         return result
 
 
+_SIP_META_KEYS = (
+    "sip_status_code",
+    "sip_status",
+    "sip_transfer_reason",
+    "sip_transfer_id",
+    "error_details",
+)
+
+
 class SipCallError(ServerError):
     """A :class:`ServerError` from a SIP dialing call (``create_sip_participant`` /
-    ``transfer_sip_participant``) that failed with a SIP response status. The SIP
-    code and reason are exposed as properties; any other error metadata remains
+    ``transfer_sip_participant``) that failed with a SIP response status, or a
+    transfer that failed for any other reason. The SIP code and reason, and the
+    transfer reason, are exposed as properties; any other error metadata remains
     available via :attr:`metadata`."""
 
     @property
@@ -109,25 +119,36 @@ def sip_status(self) -> Optional[str]:
         """The SIP reason phrase of the failed call, e.g. "Busy Here"."""
         return self.metadata.get("sip_status")
 
+    @property
+    def sip_transfer_reason(self) -> Optional[str]:
+        """Why a transfer failed, e.g. "STR_RINGING_TIMEOUT". Only set for
+        ``transfer_sip_participant``."""
+        return self.metadata.get("sip_transfer_reason")
+
+    @property
+    def sip_transfer_id(self) -> Optional[str]:
+        """The id of the failed transfer, for matching against SIP transfer logs."""
+        return self.metadata.get("sip_transfer_id")
+
     @classmethod
     def from_server_error(cls, err: ServerError) -> "SipCallError":
         return cls(err.code, err.message, status=err.status, metadata=err.metadata)
 
     def __str__(self) -> str:
         code = self.metadata.get("sip_status_code")
-        if code is None:
+        transfer_reason = self.metadata.get("sip_transfer_reason")
+        if code is None and transfer_reason is None:
             return super().__str__()
         # A clear, SIP-specific representation, including any extra metadata.
-        reason = self.metadata.get("sip_status")
-        result = f"SIP call failed: {code}"
-        if reason:
-            result += f" {reason}"
-        result += f" ({self.code})"
-        extra = {
-            k: v
-            for k, v in self.metadata.items()
-            if k not in ("sip_status_code", "sip_status", "error_details")
-        }
+        parts = []
+        if transfer_reason is not None:
+            parts.append(transfer_reason)
+        if code is not None:
+            reason = self.metadata.get("sip_status")
+            parts.append(f"{code} {reason}" if reason else str(code))
+        what = "SIP transfer failed" if transfer_reason is not None else "SIP call failed"
+        result = f"{what}: {', '.join(parts)} ({self.code})"
+        extra = {k: v for k, v in self.metadata.items() if k not in _SIP_META_KEYS}
         if extra:
             result += " [" + ", ".join(f"{k}={v}" for k, v in extra.items()) + "]"
         return result
diff --git a/tests/api/test_livekitapi.py b/tests/api/test_livekitapi.py
index 503aa01a..59dac849 100644
--- a/tests/api/test_livekitapi.py
+++ b/tests/api/test_livekitapi.py
@@ -38,6 +38,7 @@
 
 import livekit.api as api
 from livekit.api import SipCallError, ServerError
+from livekit.api.sip_service import _as_sip_error
 from livekit.protocol.rtc import SessionDescription
 
 BASE = os.getenv("LK_TEST_SERVER_URL", "http://127.0.0.1:9999")
@@ -564,6 +565,47 @@ def test_sip_no_answer():
     assert err.sip_status_code == 408
 
 
+# -- transfer failures surface the reason -------------------------------------
+
+
+def _transfer_error(**metadata: str) -> ServerError:
+    return _as_sip_error(
+        ServerError(
+            "deadline_exceeded", "call transfer failed", status=408, metadata=metadata
+        )
+    )
+
+
+def test_sip_transfer_reason():
+    err = _transfer_error(
+        sip_transfer_reason="STR_RINGING_TIMEOUT", sip_transfer_id="STR_abc"
+    )
+    assert isinstance(err, SipCallError)
+    assert err.sip_transfer_reason == "STR_RINGING_TIMEOUT"
+    assert err.sip_transfer_id == "STR_abc"
+    # No SIP response was involved in this failure.
+    assert err.sip_status_code is None
+    assert "STR_RINGING_TIMEOUT" in str(err)
+
+
+def test_sip_transfer_rejected_reports_reason_and_status():
+    err = _transfer_error(
+        sip_transfer_reason="STR_REJECTED",
+        sip_status_code="486",
+        sip_status="Busy Here",
+    )
+    assert err.sip_transfer_reason == "STR_REJECTED"
+    assert err.sip_status_code == 486
+    assert err.sip_status == "Busy Here"
+    assert "STR_REJECTED" in str(err)
+    assert "486" in str(err) and "Busy Here" in str(err)
+
+
+def test_non_sip_error_is_unchanged():
+    err = ServerError("unauthenticated", "bad token", status=401)
+    assert _as_sip_error(err) is err
+
+
 # -- cross-cutting: client-side dial timeout ----------------------------------