diff --git a/Lib/asyncio/proactor_events.py b/Lib/asyncio/proactor_events.py
index f404273c3ae5c1..acf3657c6ac9f4 100644
--- a/Lib/asyncio/proactor_events.py
+++ b/Lib/asyncio/proactor_events.py
@@ -336,10 +336,6 @@ def __init__(self, *args, **kw):
         self._empty_waiter = None
 
     def write(self, data):
-        if not isinstance(data, (bytes, bytearray, memoryview)):
-            raise TypeError(
-                f"data argument must be a bytes-like object, "
-                f"not {type(data).__name__}")
         if self._eof_written:
             raise RuntimeError('write_eof() already called')
         if self._empty_waiter is not None:
@@ -485,10 +481,6 @@ def abort(self):
         self._force_close(None)
 
     def sendto(self, data, addr=None):
-        if not isinstance(data, (bytes, bytearray, memoryview)):
-            raise TypeError('data argument must be bytes-like object (%r)',
-                            type(data))
-
         if self._address is not None and addr not in (None, self._address):
             raise ValueError(
                 f'Invalid address: must be None or {self._address}')
@@ -500,7 +492,8 @@ def sendto(self, data, addr=None):
             return
 
         # Ensure that what we buffer is immutable.
-        self._buffer.append((bytes(data), addr))
+        data = bytes(data)
+        self._buffer.append((data, addr))
         self._buffer_size += len(data) + self._header_size
 
         if self._write_fut is None:
diff --git a/Lib/asyncio/selector_events.py b/Lib/asyncio/selector_events.py
index a7e27ccf0aa856..bfa4f886169f7a 100644
--- a/Lib/asyncio/selector_events.py
+++ b/Lib/asyncio/selector_events.py
@@ -1049,9 +1049,6 @@ def _read_ready__on_eof(self):
             self.close()
 
     def write(self, data):
-        if not isinstance(data, (bytes, bytearray, memoryview)):
-            raise TypeError(f'data argument must be a bytes-like object, '
-                            f'not {type(data).__name__!r}')
         if self._eof:
             raise RuntimeError('Cannot call write() after write_eof()')
         if self._empty_waiter is not None:
@@ -1071,7 +1068,7 @@ def write(self, data):
                 n = self._sock.send(data)
             except (BlockingIOError, InterruptedError):
                 pass
-            except (SystemExit, KeyboardInterrupt):
+            except (TypeError, SystemExit, KeyboardInterrupt):
                 raise
             except BaseException as exc:
                 self._fatal_error(exc, 'Fatal write error on socket transport')
@@ -1084,7 +1081,7 @@ def write(self, data):
             self._loop._add_writer(self._sock_fd, self._write_ready)
 
         # Add it to the buffer.
-        self._buffer.append(data)
+        self._buffer.append(bytes(data))
         self._maybe_pause_protocol()
 
     def _get_sendmsg_buffer(self):
@@ -1255,10 +1252,6 @@ def _read_ready(self):
             self._protocol.datagram_received(data, addr)
 
     def sendto(self, data, addr=None):
-        if not isinstance(data, (bytes, bytearray, memoryview)):
-            raise TypeError(f'data argument must be a bytes-like object, '
-                            f'not {type(data).__name__!r}')
-
         if self._address:
             if addr not in (None, self._address):
                 raise ValueError(
@@ -1284,7 +1277,7 @@ def sendto(self, data, addr=None):
             except OSError as exc:
                 self._protocol.error_received(exc)
                 return
-            except (SystemExit, KeyboardInterrupt):
+            except (TypeError, SystemExit, KeyboardInterrupt):
                 raise
             except BaseException as exc:
                 self._fatal_error(
diff --git a/Lib/asyncio/sslproto.py b/Lib/asyncio/sslproto.py
index 74c5f0d5ca0609..6c18fbefe59a2f 100644
--- a/Lib/asyncio/sslproto.py
+++ b/Lib/asyncio/sslproto.py
@@ -214,12 +214,10 @@ def write(self, data):
         This does not block; it buffers the data and arranges for it
         to be sent out asynchronously.
         """
-        if not isinstance(data, (bytes, bytearray, memoryview)):
-            raise TypeError(f"data: expecting a bytes-like instance, "
-                            f"got {type(data).__name__}")
         if not data:
             return
-        self._ssl_protocol._write_appdata((data,))
+        # Ensure that what we buffer is immutable.
+        self._ssl_protocol._write_appdata((bytes(data),))
 
     def writelines(self, list_of_data):
         """Write a list (or any iterable) of data bytes to the transport.
diff --git a/Lib/test/test_asyncio/test_selector_events.py b/Lib/test/test_asyncio/test_selector_events.py
index 4bb5d4fb816a9a..59f260053a8970 100644
--- a/Lib/test/test_asyncio/test_selector_events.py
+++ b/Lib/test/test_asyncio/test_selector_events.py
@@ -1499,6 +1499,9 @@ def test_sendto_error_received_connected(self):
 
     def test_sendto_str(self):
         transport = self.datagram_transport()
+        def sendto(data, addr):
+            bytes(data)  # raises TypeError
+        self.sock.sendto = sendto
         self.assertRaises(TypeError, transport.sendto, 'str', ())
 
     def test_sendto_connected_addr(self):