diff --git a/packages/svelte/src/reactivity/url-search-params.js b/packages/svelte/src/reactivity/url-search-params.js
index 0aaccb111a..03387d20c1 100644
--- a/packages/svelte/src/reactivity/url-search-params.js
+++ b/packages/svelte/src/reactivity/url-search-params.js
@@ -3,9 +3,14 @@ import { get } from '../internal/client/runtime.js';
 import { increment } from './utils.js';
 
 export const REPLACE = Symbol();
+export const onChange = Symbol();
 
 export class SvelteURLSearchParams extends URLSearchParams {
 	#version = source(0);
+	/**
+	 * @type {((command: "set" | "append" | "delete" | "sort", ...args: any[])=>void ) | null}
+	 */
+	[onChange] = null;
 
 	/**
 	 * @param {URLSearchParams} params
@@ -28,8 +33,10 @@ export class SvelteURLSearchParams extends URLSearchParams {
 	 * @returns {void}
 	 */
 	append(name, value) {
+		var res = super.append(name, value);
 		increment(this.#version);
-		return super.append(name, value);
+		this[onChange]?.('append', name, value);
+		return res;
 	}
 
 	/**
@@ -42,6 +49,7 @@ export class SvelteURLSearchParams extends URLSearchParams {
 		var res = super.delete(name, value);
 		if (has_value) {
 			increment(this.#version);
+			this[onChange]?.('delete', name, value);
 		}
 		return res;
 	}
@@ -91,12 +99,14 @@ export class SvelteURLSearchParams extends URLSearchParams {
 		// if you set `foo` to 1, then foo=3 gets deleted whilst `has("foo", "1")` returns true
 		if (value_before_change !== super.getAll(name).join('')) {
 			increment(this.#version);
+			this[onChange]?.('set', name, value);
 		}
 	}
 
 	sort() {
 		var res = super.sort();
 		increment(this.#version);
+		this[onChange]?.('sort');
 		return res;
 	}
 
diff --git a/packages/svelte/src/reactivity/url.js b/packages/svelte/src/reactivity/url.js
index bf575b9e2c..822481c428 100644
--- a/packages/svelte/src/reactivity/url.js
+++ b/packages/svelte/src/reactivity/url.js
@@ -1,6 +1,6 @@
 import { source, set } from '../internal/client/reactivity/sources.js';
 import { get } from '../internal/client/runtime.js';
-import { REPLACE, SvelteURLSearchParams } from './url-search-params.js';
+import { onChange, REPLACE, SvelteURLSearchParams } from './url-search-params.js';
 
 export class SvelteURL extends URL {
 	#protocol = source(super.protocol);
@@ -20,6 +20,11 @@ export class SvelteURL extends URL {
 		url = new URL(url, base);
 		super(url);
 		this.#searchParams[REPLACE](url.searchParams);
+		this.#searchParams[onChange] = (command, ...args) => {
+			// by doing this, we sync SvelteSearchParams with internal implementation of URL.searchParams
+			// @ts-ignore
+			super.searchParams[command](...args);
+		};
 	}
 
 	get hash() {
diff --git a/packages/svelte/src/reactivity/url.test.ts b/packages/svelte/src/reactivity/url.test.ts
index 6956ae0198..d93fb90afc 100644
--- a/packages/svelte/src/reactivity/url.test.ts
+++ b/packages/svelte/src/reactivity/url.test.ts
@@ -4,7 +4,7 @@ import { SvelteURL } from './url.js';
 import { assert, test } from 'vitest';
 
 test('url.hash', () => {
-	const url = new SvelteURL('http://google.com');
+	const url = new SvelteURL('https://svelte.dev');
 	const log: any = [];
 
 	const cleanup = effect_root(() => {
@@ -18,7 +18,7 @@ test('url.hash', () => {
 	});
 
 	flushSync(() => {
-		url.href = 'http://google.com/a/b/c#def';
+		url.href = 'https://svelte.dev/a/b/c#def';
 	});
 
 	flushSync(() => {
@@ -31,6 +31,44 @@ test('url.hash', () => {
 	cleanup();
 });
 
+test('url.href', () => {
+	const url = new SvelteURL('https://svelte.dev?foo=bar&t=123');
+	const log: any = [];
+
+	const cleanup = effect_root(() => {
+		render_effect(() => {
+			log.push(url.href);
+		});
+	});
+
+	flushSync(() => {
+		url.search = '?q=kit&foo=baz';
+	});
+
+	flushSync(() => {
+		// changes from searchParams should be synced to URL instance as well
+		url.searchParams.append('foo', 'qux');
+	});
+
+	flushSync(() => {
+		url.searchParams.delete('foo');
+	});
+
+	flushSync(() => {
+		url.searchParams.set('love', 'svelte5');
+	});
+
+	assert.deepEqual(log, [
+		'https://svelte.dev/?foo=bar&t=123',
+		'https://svelte.dev/?q=kit&foo=baz',
+		'https://svelte.dev/?q=kit&foo=baz&foo=qux',
+		'https://svelte.dev/?q=kit',
+		'https://svelte.dev/?q=kit&love=svelte5'
+	]);
+
+	cleanup();
+});
+
 test('url.searchParams', () => {
 	const url = new SvelteURL('https://svelte.dev?foo=bar&t=123');
 	const log: any = [];
@@ -76,3 +114,7 @@ test('url.searchParams', () => {
 
 	cleanup();
 });
+
+test('URL.instanceOf', () => {
+	assert.equal(new SvelteURL('https://svelte.dev') instanceof URL, true);
+});
diff --git a/vitest.config.js b/vitest.config.js
index 86c5c99d0e..caeda27e30 100644
--- a/vitest.config.js
+++ b/vitest.config.js
@@ -30,9 +30,9 @@ export default defineConfig({
 		dir: '.',
 		reporters: ['dot'],
 		include: [
-			'packages/svelte/**/*.test.ts'
-			// 'packages/svelte/tests/*/test.ts',
-			// 'packages/svelte/tests/runtime-browser/test-ssr.ts'
+			'packages/svelte/**/*.test.ts',
+			'packages/svelte/tests/*/test.ts',
+			'packages/svelte/tests/runtime-browser/test-ssr.ts'
 		],
 		exclude: [...configDefaults.exclude, '**/samples/**'],
 		coverage: {