diff --git a/packages/lit-element/src/experimental-hydrate-support.ts b/packages/lit-element/src/experimental-hydrate-support.ts
index 0dc785fb40..8d63f686e1 100644
--- a/packages/lit-element/src/experimental-hydrate-support.ts
+++ b/packages/lit-element/src/experimental-hydrate-support.ts
@@ -8,6 +8,8 @@
  * LitElement support for hydration of content rendered using lit-ssr.
  *
  * @packageDocumentation
+ *
+ * @deprecated Moved to `@lit-labs/ssr-client/lit-element-hydrate-support.js`.
  */
 
 import type {PropertyValues} from '@lit/reactive-element';
@@ -101,3 +103,8 @@ globalThis.litElementHydrateSupport = ({
     }
   };
 };
+
+console.warn(
+  'Import from `lit-element/experimental-hydrate-support.js` is deprecated.' +
+    'Import `@lit-labs/ssr-client/lit-element-hydrate-support.js` instead.'
+);
diff --git a/packages/lit-html/src/experimental-hydrate.ts b/packages/lit-html/src/experimental-hydrate.ts
index a8f3478d01..c5022b6cbb 100644
--- a/packages/lit-html/src/experimental-hydrate.ts
+++ b/packages/lit-html/src/experimental-hydrate.ts
@@ -113,6 +113,9 @@ type ChildPartState =
  * @param rootValue
  * @param container
  * @param userOptions
+ *
+ * @deprecated This has been moved to `@lit-labs/ssr-client` and will be removed
+ * in a future release.
  */
 export const hydrate = (
   rootValue: unknown,