diff --git a/components/templates/src/builtins/sitemap.xml b/components/templates/src/builtins/sitemap.xml
index 6d55d37..2154a5b 100644
--- a/components/templates/src/builtins/sitemap.xml
+++ b/components/templates/src/builtins/sitemap.xml
@@ -1,4 +1,4 @@
-<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
+<urlset xmlns="https://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd">
     {% for sitemap_entry in entries %}
         <url>
             <loc>{{ sitemap_entry.permalink | safe }}</loc>
diff --git a/components/templates/src/builtins/split_sitemap_index.xml b/components/templates/src/builtins/split_sitemap_index.xml
index 1b883e4..171665c 100644
--- a/components/templates/src/builtins/split_sitemap_index.xml
+++ b/components/templates/src/builtins/split_sitemap_index.xml
@@ -1,4 +1,4 @@
-<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
+<sitemapindex xmlns="https://www.sitemaps.org/schemas/sitemap/0.9/siteindex.xsd">
     {% for sitemap in sitemaps %}
         <sitemap>
             <loc>{{ sitemap }}</loc>