diff --git a/pycyphal/_version.py b/pycyphal/_version.py
index 9813fabb..e7f9341b 100644
--- a/pycyphal/_version.py
+++ b/pycyphal/_version.py
@@ -1 +1 @@
-__version__ = "1.27.0"
+__version__ = "1.27.1"
diff --git a/pycyphal/transport/serial/_serial.py b/pycyphal/transport/serial/_serial.py
index 0b093e29..a477d88b 100644
--- a/pycyphal/transport/serial/_serial.py
+++ b/pycyphal/transport/serial/_serial.py
@@ -452,7 +452,13 @@ def callback(ts: Timestamp, buf: memoryview, frame: typing.Optional[SerialFrame]
                     self._serial_port,
                 )
             self._closed = True
-            self._serial_port.close()
+            try:
+                self._serial_port.close()
+            except Exception:
+                # close() is not atomic (see __init__), so when SerialTransport.close() runs at the
+                # same time, the reader thread can try to close an already-closed port. The resulting
+                # OSError is harmless, so ignore it.
+                pass
 
         finally:
             _logger.debug("%s: Reader thread is exiting. Head aega.", self)