diff --git a/mercurial/subrepo.py b/mercurial/subrepo.py
--- a/mercurial/subrepo.py
+++ b/mercurial/subrepo.py
@@ -517,7 +517,7 @@ class abstractsubrepo(object):
             flags = self.fileflags(name)
             mode = 'x' in flags and 0755 or 0644
             symlink = 'l' in flags
-            archiver.addfile(self.wvfs.reljoin(prefix, self._path, name),
+            archiver.addfile(prefix + self._path + '/' + name,
                              mode, symlink, self.filedata(name))
             self.ui.progress(_('archiving (%s)') % relpath, i + 1,
                              unit=_('files'), total=total)
@@ -731,8 +731,7 @@ class hgsubrepo(abstractsubrepo):
         for subpath in ctx.substate:
             s = subrepo(ctx, subpath)
             submatch = matchmod.narrowmatcher(subpath, match)
-            total += s.archive(
-                archiver, self.wvfs.reljoin(prefix, self._path), submatch)
+            total += s.archive(archiver, prefix + self._path + '/', submatch)
         return total
 
     @annotatesubrepoerror
@@ -1675,7 +1674,7 @@ class gitsubrepo(abstractsubrepo):
                 data = info.linkname
             else:
                 data = tar.extractfile(info).read()
-            archiver.addfile(self.wvfs.reljoin(prefix, self._path, info.name),
+            archiver.addfile(prefix + self._path + '/' + info.name,
                              info.mode, info.issym(), data)
             total += 1
             self.ui.progress(_('archiving (%s)') % relpath, i + 1,
diff --git a/tests/test-subrepo-deep-nested-change.t b/tests/test-subrepo-deep-nested-change.t
--- a/tests/test-subrepo-deep-nested-change.t
+++ b/tests/test-subrepo-deep-nested-change.t
@@ -309,21 +309,17 @@ Exclude large files from main and sub-su
 
 Exclude normal files from main and sub-sub repo
 
-  $ hg --config extensions.largefiles= archive -S -X '**.txt' ../archive_lf
-  $ find ../archive_lf | sort
-  ../archive_lf
-  ../archive_lf/.hgsub
-  ../archive_lf/.hgsubstate
-  ../archive_lf/large.bin
-  ../archive_lf/main
-  ../archive_lf/sub1
-  ../archive_lf/sub1/.hgsub
-  ../archive_lf/sub1/.hgsubstate
-  ../archive_lf/sub1/sub1
-  ../archive_lf/sub1/sub2
-  ../archive_lf/sub1/sub2/large.bin
-  ../archive_lf/sub1/sub2/sub2
-  $ rm -rf ../archive_lf
+  $ hg --config extensions.largefiles= archive -S -X '**.txt' ../archive_lf.tgz
+  $ tar -tzf ../archive_lf.tgz | sort
+  archive_lf/.hgsub
+  archive_lf/.hgsubstate
+  archive_lf/large.bin
+  archive_lf/main
+  archive_lf/sub1/.hgsub
+  archive_lf/sub1/.hgsubstate
+  archive_lf/sub1/sub1
+  archive_lf/sub1/sub2/large.bin
+  archive_lf/sub1/sub2/sub2
 
 Include normal files from within a largefiles subrepo
 
diff --git a/tests/test-subrepo-git.t b/tests/test-subrepo-git.t
--- a/tests/test-subrepo-git.t
+++ b/tests/test-subrepo-git.t
@@ -325,6 +325,14 @@ archive subrepos
   ../archive_x/s
   ../archive_x/s/g
 
+  $ hg -R ../tc archive -S ../archive.tgz 2>/dev/null
+  $ tar -tzf ../archive.tgz | sort
+  archive/.hg_archival.txt
+  archive/.hgsub
+  archive/.hgsubstate
+  archive/a
+  archive/s/g
+
 create nested repo
 
   $ cd ..
diff --git a/tests/test-subrepo-recursion.t b/tests/test-subrepo-recursion.t
--- a/tests/test-subrepo-recursion.t
+++ b/tests/test-subrepo-recursion.t
@@ -434,6 +434,18 @@ Note there's a slight output glitch on n
   cloning subrepo foo/bar from $TESTTMP/repo/foo/bar (glob)
 #endif
 
+Archive + subrepos uses '/' for all component separators
+
+  $ tar -tzf ../archive.tar.gz | sort
+  archive/.hg_archival.txt
+  archive/.hgsub
+  archive/.hgsubstate
+  archive/foo/.hgsub
+  archive/foo/.hgsubstate
+  archive/foo/bar/z.txt
+  archive/foo/y.txt
+  archive/x.txt
+
 The newly cloned subrepos contain no working copy:
 
   $ hg -R foo summary