diff -r 5c09e1c57200 Doc/library/zipfile.rst
--- a/Doc/library/zipfile.rst	Wed Mar 20 20:16:47 2013 +0100
+++ b/Doc/library/zipfile.rst	Wed Mar 20 17:40:19 2013 -0700
@@ -429,6 +429,27 @@
 
    Name of the file in the archive.
 
+   Officially, the Zip specification allows for filenames in one of two
+   encodings: ``utf-8`` or ``cp437``.  If all software that created zip
+   files knew the encodings of the filenames they were putting into a zip
+   file, they'd be able to use one of these two encodings to make filenames
+   look the same to both the user who created the zip file and the user who
+   unzipped it. Unfortunately, tools to create zip files often encounter
+   filenames that they don't know the encoding of.  When this happens, all
+   known tools (including this module) encode the filenames using
+   ``cp437`` to preserve the filename's actual byte values.  When python
+   then loads the filename from the zipfile, it will use ``cp437`` to
+   decode the filenames into a :class:`str`.  if the original encoding was
+   not ``cp437`` the filenames may be garbled.  If you know what encoding
+   they really were you can make them readable by reencoding to ``cp437``
+   and then decoding using the proper encoding.  For instance::
+
+     >>> zi.filename
+     'CafΘ_Espa±a.txt'
+     >>> zi.filename.encode('cp437').decode('latin-1')
+     'Café_España.txt'
+
+
 
 .. attribute:: ZipInfo.date_time
 
diff -r 5c09e1c57200 Lib/test/test_zipfile.py
--- a/Lib/test/test_zipfile.py	Wed Mar 20 20:16:47 2013 +0100
+++ b/Lib/test/test_zipfile.py	Wed Mar 20 17:40:19 2013 -0700
@@ -1040,6 +1040,19 @@
             self.assertEqual(zf.filelist[0].filename, "foo.txt")
             self.assertEqual(zf.filelist[1].filename, "\xf6.txt")
 
+    def test_undecodable_filenames(self):
+        undecodable = "\xf6.txt".encode("cp437").decode("utf-8", errors="surrogateescape")
+        with zipfile.ZipFile(TESTFN, "w") as zf:
+            zf.writestr("foo.txt", "Test for unicode filename")
+            zf.writestr("\xf6.txt", "Test for unicode filename")
+            zf.writestr(undecodable, "Test for undecodable filename")
+            self.assertIsInstance(zf.infolist()[2].filename, str)
+
+        with zipfile.ZipFile(TESTFN, "r") as zf:
+            self.assertEqual(zf.filelist[0].filename, "foo.txt")
+            self.assertEqual(zf.filelist[1].filename, "\xf6.txt")
+            self.assertEqual(zf.filelist[2].filename, "\xf6.txt")
+
     def test_create_non_existent_file_for_append(self):
         if os.path.exists(TESTFN):
             os.unlink(TESTFN)
diff -r 5c09e1c57200 Lib/zipfile.py
--- a/Lib/zipfile.py	Wed Mar 20 20:16:47 2013 +0100
+++ b/Lib/zipfile.py	Wed Mar 20 17:40:19 2013 -0700
@@ -402,10 +402,22 @@
         return header + filename + extra
 
     def _encodeFilenameFlags(self):
+        # filenames in zip files can consist of any set of bytes (The
+        # *characters* the bytes represent  are supposed to be from Code Page
+        # 437 but implementations I checked exploit the fact that Code Page 437
+        # can contain any byte sequence to simply encode any byte sequence
+        # without attempting to determine if it's Code Page 437.
+
+        # Since older python-stdlib separates ascii from utf-8 we don't set the
+        # utf-8 flag for ascii-only filenames below.  However, since utf-8 is a
+        # superset of ascii, it would be legal to do so.
         try:
             return self.filename.encode('ascii'), self.flag_bits
         except UnicodeEncodeError:
-            return self.filename.encode('utf-8'), self.flag_bits | 0x800
+            try:
+                return self.filename.encode('utf-8'), self.flag_bits | 0x800
+            except UnicodeEncodeError:
+                return self.filename.encode('utf-8', errors='surrogateescape'), self.flag_bits
 
     def _decodeExtra(self):
         # Try to decode the extra field.
@@ -997,6 +1009,10 @@
                 print(centdir)
             filename = fp.read(centdir[_CD_FILENAME_LENGTH])
             flags = centdir[5]
+            # Caveat on filenames: the spec says that encodings are either
+            # utf-8 or cp437 but in practice zipfiles use the cp437 fallback to
+            # store unknown encodings.  See the zipfile.ZipInfo documentation
+            # if you're confused by what this means.
             if flags & 0x800:
                 # UTF-8 file names extension
                 filename = filename.decode('utf-8')
@@ -1153,6 +1169,10 @@
                 # strong encryption
                 raise NotImplementedError("strong encryption (flag bit 6)")
 
+            # Caveat on filenames: the spec says that encodings are either
+            # utf-8 or cp437 but in practice zipfiles use the cp437 fallback to
+            # store unknown encodings.  See the zipfile.ZipInfo documentation
+            # if you're confused by what this means
             if zinfo.flag_bits & 0x800:
                 # UTF-8 filename
                 fname_str = fname.decode("utf-8")
diff -r 5c09e1c57200 Misc/NEWS
--- a/Misc/NEWS	Wed Mar 20 20:16:47 2013 +0100
+++ b/Misc/NEWS	Wed Mar 20 17:40:19 2013 -0700
@@ -974,6 +974,9 @@
 - ctypes.call_commethod was removed, since its only usage was in the defunct
   samples directory.
 
+- Issue #16310: Fixed zipfile to handle filenames that are not decodable in the
+  present locale
+
 Extension Modules
 -----------------