diff --git a/.changeset/ten-gorillas-itch.md b/.changeset/ten-gorillas-itch.md
new file mode 100644
index 000000000000..15790d6cbbbe
--- /dev/null
+++ b/.changeset/ten-gorillas-itch.md
@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+Throw error if browser.hydrate is false and browser.router is true
diff --git a/packages/kit/src/core/config/index.spec.js b/packages/kit/src/core/config/index.spec.js
index 3cd626d4910c..e9d6e0e66c44 100644
--- a/packages/kit/src/core/config/index.spec.js
+++ b/packages/kit/src/core/config/index.spec.js
@@ -246,6 +246,19 @@ test('fails if kit.appDir ends with slash', () => {
 	}, /^config\.kit\.appDir cannot start or end with '\/'. See https:\/\/kit\.svelte\.dev\/docs\/configuration$/);
 });
 
+test('fails if browser.hydrate is false and browser.router is true', () => {
+	assert.throws(() => {
+		validate_config({
+			kit: {
+				browser: {
+					hydrate: false,
+					router: true
+				}
+			}
+		});
+	}, /^config\.kit\.browser\.router cannot be true if config\.kit\.browser\.hydrate is false$/);
+});
+
 test('fails if paths.base is not root-relative', () => {
 	assert.throws(() => {
 		validate_config({
diff --git a/packages/kit/src/core/config/options.js b/packages/kit/src/core/config/options.js
index 9d89fd4ee6fe..c82f008d8253 100644
--- a/packages/kit/src/core/config/options.js
+++ b/packages/kit/src/core/config/options.js
@@ -107,9 +107,14 @@ const options = object(
 				return input;
 			}),
 
-			browser: object({
-				hydrate: boolean(true),
-				router: boolean(true)
+			browser: validate({ hydrate: true, router: true }, (input, keypath) => {
+				const value = object({ hydrate: boolean(true), router: boolean(true) })(input, keypath);
+				if (!value.hydrate && value.router) {
+					throw new Error(
+						'config.kit.browser.router cannot be true if config.kit.browser.hydrate is false'
+					);
+				}
+				return value;
 			}),
 
 			csp: object({