diff --git a/runtime/ftplugin/swig.vim b/runtime/ftplugin/swig.vim
index 506c929a43..a8cee72c55 100644
--- a/runtime/ftplugin/swig.vim
+++ b/runtime/ftplugin/swig.vim
@@ -2,6 +2,7 @@
 " Language:	SWIG
 " Maintainer:	Julien Marrec <julien.marrec 'at' gmail com>
 " Last Change:	2023 November 23
+" 2025 July 14 by Vim project: set 'comment'/'commentstring' options
 
 " Only do this when not done yet for this buffer
 if exists("b:did_ftplugin")
@@ -9,5 +10,7 @@ if exists("b:did_ftplugin")
 endif
 let b:did_ftplugin = 1
 
-let b:undo_ftplugin = "setlocal iskeyword<"
+let b:undo_ftplugin = "setlocal iskeyword< comments< commentstring<"
 setlocal iskeyword+=%
+setlocal comments=sO:*\ -,mO:*\ \ ,exO:*/,s1:/*,mb:*,ex:*/,://
+setlocal commentstring=//\ %s