diff --git a/.changeset/blur-during-navigation.md b/.changeset/blur-during-navigation.md
new file mode 100644
index 000000000000..aa51e5b2ce79
--- /dev/null
+++ b/.changeset/blur-during-navigation.md
@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+fix: blur active element before component update during navigation so that blur/focusout handlers fire while old component data is still valid
diff --git a/packages/kit/src/runtime/client/client.js b/packages/kit/src/runtime/client/client.js
index 0faada3d4b01..683960163f62 100644
--- a/packages/kit/src/runtime/client/client.js
+++ b/packages/kit/src/runtime/client/client.js
@@ -1739,6 +1739,16 @@ async function navigate({
 			navigation_result.props.page.url = url;
 		}
 
+		// Remove focus before updating the component tree, so that blur/focusout
+		// handlers fire while the old component's data is still valid (#14575)
+		if (
+			!keepfocus &&
+			document.activeElement instanceof HTMLElement &&
+			document.activeElement !== document.body
+		) {
+			document.activeElement.blur();
+		}
+
 		const fork = load_cache_fork && (await load_cache_fork);
 
 		if (fork) {
diff --git a/packages/kit/test/apps/basics/src/routes/accessibility/blur-during-navigation/other/+page.svelte b/packages/kit/test/apps/basics/src/routes/accessibility/blur-during-navigation/other/+page.svelte
new file mode 100644
index 000000000000..77976b8a85f6
--- /dev/null
+++ b/packages/kit/test/apps/basics/src/routes/accessibility/blur-during-navigation/other/+page.svelte
@@ -0,0 +1,2 @@
+<h1>Other page</h1>
+<a href="/accessibility/blur-during-navigation/page-with-input">Back</a>
diff --git a/packages/kit/test/apps/basics/src/routes/accessibility/blur-during-navigation/page-with-input/+page.js b/packages/kit/test/apps/basics/src/routes/accessibility/blur-during-navigation/page-with-input/+page.js
new file mode 100644
index 000000000000..bc2650dd05ed
--- /dev/null
+++ b/packages/kit/test/apps/basics/src/routes/accessibility/blur-during-navigation/page-with-input/+page.js
@@ -0,0 +1,3 @@
+export function load() {
+	return { message: 'hello' };
+}
diff --git a/packages/kit/test/apps/basics/src/routes/accessibility/blur-during-navigation/page-with-input/+page.svelte b/packages/kit/test/apps/basics/src/routes/accessibility/blur-during-navigation/page-with-input/+page.svelte
new file mode 100644
index 000000000000..3bba40880950
--- /dev/null
+++ b/packages/kit/test/apps/basics/src/routes/accessibility/blur-during-navigation/page-with-input/+page.svelte
@@ -0,0 +1,14 @@
+<script>
+	let { data } = $props();
+
+	function handleBlur() {
+		// Without the fix, data was already nulled when blur fired during
+		// navigation, causing "Cannot read properties of undefined".
+		// We write to window so the result survives component teardown.
+		/** @type {any} */ (window).__blur_test_result = data.message;
+	}
+</script>
+
+<h1>Blur test</h1>
+<input id="blur-input" onblur={handleBlur} />
+<a href="/accessibility/blur-during-navigation/other">Go to other</a>
diff --git a/packages/kit/test/apps/basics/test/cross-platform/client.test.js b/packages/kit/test/apps/basics/test/cross-platform/client.test.js
index 33afa996226e..42a24031e720 100644
--- a/packages/kit/test/apps/basics/test/cross-platform/client.test.js
+++ b/packages/kit/test/apps/basics/test/cross-platform/client.test.js
@@ -122,6 +122,25 @@ test.describe('a11y', () => {
 		).toBe('BODY');
 		expect(await page.evaluate(() => document.activeElement?.nodeName)).toBe('BODY');
 	});
+
+	test('blur handler can access data during navigation', async ({ page, app }) => {
+		const errors = /** @type {string[]} */ ([]);
+		page.on('pageerror', (err) => errors.push(err.message));
+
+		await page.goto('/accessibility/blur-during-navigation/page-with-input');
+
+		// Focus the input
+		await page.locator('#blur-input').focus();
+
+		// Navigate away — this triggers blur on the focused input.
+		// Without the fix, data would be nulled before blur fired, causing a TypeError.
+		await app.goto('/accessibility/blur-during-navigation/other');
+
+		expect(errors).toEqual([]);
+
+		// The blur handler should have been able to read data.message
+		expect(await page.evaluate(() => /** @type {any} */ (window).__blur_test_result)).toBe('hello');
+	});
 });
 
 test.describe('Navigation lifecycle functions', () => {