diff --git a/Lib/io.py b/Lib/io.py
index 940c4c776c8..d85ed49d150 100644
--- a/Lib/io.py
+++ b/Lib/io.py
@@ -831,9 +831,9 @@ def seek(self, pos, whence=0):
         except AttributeError as err:
             raise TypeError("an integer is required") from err
         if whence == 0:
-            self._pos = max(0, pos)
             if pos < 0:
                 raise ValueError("negative seek position %r" % (pos,))
+            self._pos = max(0, pos)
         elif whence == 1:
             self._pos = max(0, self._pos + pos)
         elif whence == 2: