diff --git a/routes/blog/[slug].tsx b/routes/blog/[slug].tsx
index 82e19c154..ec8fa3427 100644
--- a/routes/blog/[slug].tsx
+++ b/routes/blog/[slug].tsx
@@ -22,7 +22,10 @@ export default async function BlogPostPage(_req: Request, ctx: RouteContext) {
       <main class="p-4 flex-1">
         <h1 class="text-4xl font-bold">{post.title}</h1>
         {date && (
-          <time class="text-gray-500">
+          <time
+            dateTime={post.publishedAt.toISOString()}
+            class="text-gray-500"
+          >
             {date}
           </time>
         )}
diff --git a/routes/blog/index.tsx b/routes/blog/index.tsx
index c6d962fe7..aada89c29 100644
--- a/routes/blog/index.tsx
+++ b/routes/blog/index.tsx
@@ -12,7 +12,10 @@ function PostCard(props: Post) {
           {props.title}
         </h2>
         {props.publishedAt.toString() !== "Invalid Date" && (
-          <time class="text-gray-500">
+          <time
+            dateTime={props.publishedAt.toISOString()}
+            class="text-gray-500"
+          >
             {props.publishedAt.toLocaleDateString("en-US", {
               dateStyle: "long",
             })}