diff --git a/newsfragments/3509.bugfix.rst b/newsfragments/3509.bugfix.rst
new file mode 100644
index 0000000000..2966f4706f
--- /dev/null
+++ b/newsfragments/3509.bugfix.rst
@@ -0,0 +1,4 @@
+On Windows, :func:`trio.lowlevel.wait_readable`, :func:`trio.lowlevel.wait_writable`
+and :func:`trio.lowlevel.notify_closing` raised ``BusyResourceError`` and
+``ClosedResourceError`` without any message. They now explain themselves, as they
+already did on the epoll and kqueue backends.
diff --git a/src/trio/_core/_io_windows.py b/src/trio/_core/_io_windows.py
index 7b789c3dec..99f31aea0a 100644
--- a/src/trio/_core/_io_windows.py
+++ b/src/trio/_core/_io_windows.py
@@ -740,7 +740,9 @@ async def _afd_poll(self, sock: _HasFileNo | int, mode: str) -> None:
             waiters = AFDWaiters()
             self._afd_waiters[base_handle] = waiters
         if getattr(waiters, mode) is not None:
-            raise _core.BusyResourceError
+            raise _core.BusyResourceError(
+                "another task is already reading / writing this socket",
+            )
         setattr(waiters, mode, _core.current_task())
         # Could potentially raise if the handle is somehow invalid; that's OK,
         # we let it escape.
@@ -822,7 +824,10 @@ def notify_closing(self, handle: Handle | int | _HasFileNo) -> None:
         handle = _get_base_socket(handle)
         waiters = self._afd_waiters.get(handle)
         if waiters is not None:
-            wake_all(waiters, _core.ClosedResourceError())
+            wake_all(
+                waiters,
+                _core.ClosedResourceError("another task closed this socket"),
+            )
             self._refresh_afd(handle)
 
     ################################################################