diff --git a/.changeset/async-hydration-orphan-nodes.md b/.changeset/async-hydration-orphan-nodes.md
new file mode 100644
index 0000000000..4c35d6b74e
--- /dev/null
+++ b/.changeset/async-hydration-orphan-nodes.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: properly track effect end node for async sibling component
\ No newline at end of file
diff --git a/packages/svelte/src/internal/client/dom/blocks/async.js b/packages/svelte/src/internal/client/dom/blocks/async.js
index 170529a6b9..78e2ed44be 100644
--- a/packages/svelte/src/internal/client/dom/blocks/async.js
+++ b/packages/svelte/src/internal/client/dom/blocks/async.js
@@ -9,6 +9,7 @@ import {
 	set_hydrating,
 	skip_nodes
 } from '../hydration.js';
+import { assign_nodes } from '../template.js';
 
 /**
  * @param {TemplateNode} node
@@ -23,6 +24,7 @@ export function async(node, blockers = [], expressions = [], fn) {
 	if (was_hydrating) {
 		hydrate_next();
 		end = skip_nodes(false);
+		assign_nodes(node, end); // Necessary if this wraps the sole child of a block, else end marker can be wrong
 	}
 
 	if (expressions.length === 0 && blockers.every((b) => b.settled)) {
diff --git a/packages/svelte/tests/hydration/test.ts b/packages/svelte/tests/hydration/test.ts
index d2bf6fde34..0050130817 100644
--- a/packages/svelte/tests/hydration/test.ts
+++ b/packages/svelte/tests/hydration/test.ts
@@ -72,7 +72,7 @@ const { test, run } = suite<HydrationTest>(async (config, cwd) => {
 	const target = window.document.body;
 	const head = window.document.head;
 
-	const rendered = render((await import(`${cwd}/_output/server/main.svelte.js`)).default, {
+	const rendered = await render((await import(`${cwd}/_output/server/main.svelte.js`)).default, {
 		props: config.server_props ?? config.props ?? {},
 		idPrefix: config?.id_prefix
 	});
@@ -80,8 +80,8 @@ const { test, run } = suite<HydrationTest>(async (config, cwd) => {
 	const override = read(`${cwd}/_override.html`);
 	const override_head = read(`${cwd}/_override_head.html`);
 
-	fs.writeFileSync(`${cwd}/_output/body.html`, rendered.html + '\n');
-	target.innerHTML = override ?? rendered.html;
+	fs.writeFileSync(`${cwd}/_output/body.html`, rendered.body + '\n');
+	target.innerHTML = override ?? rendered.body;
 
 	if (rendered.head) {
 		fs.writeFileSync(`${cwd}/_output/head.html`, rendered.head + '\n');
@@ -145,7 +145,7 @@ const { test, run } = suite<HydrationTest>(async (config, cwd) => {
 
 		flushSync();
 
-		const expected = read(`${cwd}/_expected.html`) ?? rendered.html;
+		const expected = read(`${cwd}/_expected.html`) ?? rendered.body;
 		assert_html_equal(target.innerHTML, expected);
 
 		if (rendered.head) {
diff --git a/packages/svelte/tests/runtime-runes/samples/async-sole-if-child/Child.svelte b/packages/svelte/tests/runtime-runes/samples/async-sole-if-child/Child.svelte
new file mode 100644
index 0000000000..304b7bd8a9
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-sole-if-child/Child.svelte
@@ -0,0 +1,7 @@
+<script>
+	import Header from './Header.svelte';
+	import Footer from './Footer.svelte';
+</script>
+ 
+<Header />
+<Footer />
diff --git a/packages/svelte/tests/runtime-runes/samples/async-sole-if-child/Footer.svelte b/packages/svelte/tests/runtime-runes/samples/async-sole-if-child/Footer.svelte
new file mode 100644
index 0000000000..4c05c3d1ca
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-sole-if-child/Footer.svelte
@@ -0,0 +1 @@
+<footer>footer</footer>
\ No newline at end of file
diff --git a/packages/svelte/tests/runtime-runes/samples/async-sole-if-child/Header.svelte b/packages/svelte/tests/runtime-runes/samples/async-sole-if-child/Header.svelte
new file mode 100644
index 0000000000..bb4683e48e
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-sole-if-child/Header.svelte
@@ -0,0 +1 @@
+<header>header</header>
\ No newline at end of file
diff --git a/packages/svelte/tests/runtime-runes/samples/async-sole-if-child/_config.js b/packages/svelte/tests/runtime-runes/samples/async-sole-if-child/_config.js
new file mode 100644
index 0000000000..842a314f73
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-sole-if-child/_config.js
@@ -0,0 +1,38 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, target }) {
+		await tick();
+		const [toggle] = target.querySelectorAll('button');
+
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				<button>toggle</button>
+				<header>header</header>
+				<footer>footer</footer>
+			`
+		);
+
+		toggle.click();
+		await tick();
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				<button>toggle</button>
+			`
+		);
+
+		toggle.click();
+		await tick();
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				<button>toggle</button>
+				<header>header</header>
+				<footer>footer</footer>
+			`
+		);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-sole-if-child/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-sole-if-child/main.svelte
new file mode 100644
index 0000000000..9a061501dd
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-sole-if-child/main.svelte
@@ -0,0 +1,11 @@
+<script>
+	import Child from './Child.svelte';
+
+	let show = $state(true);
+</script>
+
+<button onclick={() => (show = !show)}>toggle</button>
+
+{#if show}
+	<Child gate={await Promise.resolve(true)} />
+{/if}