diff --git a/stdlib/codecs.pyi b/stdlib/codecs.pyi
index a7b60e38df11..26c4a5801678 100644
--- a/stdlib/codecs.pyi
+++ b/stdlib/codecs.pyi
@@ -1,5 +1,5 @@
 import types
-from _typeshed import Self
+from _typeshed import ReadableBuffer, Self
 from abc import abstractmethod
 from collections.abc import Callable, Generator, Iterable
 from typing import Any, BinaryIO, Protocol, TextIO
@@ -173,7 +173,7 @@ class IncrementalDecoder:
     errors: str
     def __init__(self, errors: str = ...) -> None: ...
     @abstractmethod
-    def decode(self, input: bytes, final: bool = ...) -> str: ...
+    def decode(self, input: ReadableBuffer, final: bool = ...) -> str: ...
     def reset(self) -> None: ...
     def getstate(self) -> tuple[bytes, int]: ...
     def setstate(self, state: tuple[bytes, int]) -> None: ...
@@ -190,8 +190,8 @@ class BufferedIncrementalDecoder(IncrementalDecoder):
     buffer: bytes
     def __init__(self, errors: str = ...) -> None: ...
     @abstractmethod
-    def _buffer_decode(self, input: bytes, errors: str, final: bool) -> tuple[str, int]: ...
-    def decode(self, input: bytes, final: bool = ...) -> str: ...
+    def _buffer_decode(self, input: ReadableBuffer, errors: str, final: bool) -> tuple[str, int]: ...
+    def decode(self, input: ReadableBuffer, final: bool = ...) -> str: ...
 
 # TODO: it is not possible to specify the requirement that all other
 # attributes and methods are passed-through from the stream.
diff --git a/stdlib/io.pyi b/stdlib/io.pyi
index 2d3aadc483f0..9c4c769fe34b 100644
--- a/stdlib/io.pyi
+++ b/stdlib/io.pyi
@@ -190,7 +190,7 @@ class StringIO(TextIOWrapper):
 
 class IncrementalNewlineDecoder(codecs.IncrementalDecoder):
     def __init__(self, decoder: codecs.IncrementalDecoder | None, translate: bool, errors: str = ...) -> None: ...
-    def decode(self, input: bytes | str, final: bool = ...) -> str: ...
+    def decode(self, input: ReadableBuffer | str, final: bool = ...) -> str: ...
     @property
     def newlines(self) -> str | tuple[str, ...] | None: ...
     def setstate(self, __state: tuple[bytes, int]) -> None: ...