diff --git a/packages/browser/src/client/orchestrator.ts b/packages/browser/src/client/orchestrator.ts
index 10d4c0bf4f73..d9ce4a1e243f 100644
--- a/packages/browser/src/client/orchestrator.ts
+++ b/packages/browser/src/client/orchestrator.ts
@@ -273,10 +273,25 @@ async function setIframeViewport(
   if (ui) {
     await ui.setIframeViewport(width, height)
   }
-  else {
+  else if (getBrowserState().provider === 'webdriverio') {
     iframe.style.width = `${width}px`
     iframe.style.height = `${height}px`
   }
+  else {
+    const scale = Math.min(
+      1,
+      iframe.parentElement!.parentElement!.clientWidth / width,
+      iframe.parentElement!.parentElement!.clientHeight / height,
+    )
+    iframe.parentElement!.style.cssText = `
+      width: ${width}px;
+      height: ${height}px;
+      transform: scale(${scale});
+      transform-origin: left top;
+    `
+    iframe.parentElement?.setAttribute('data-scale', String(scale))
+    await new Promise(r => requestAnimationFrame(r))
+  }
 }
 
 function debug(...args: unknown[]) {
diff --git a/packages/browser/src/client/tester/context.ts b/packages/browser/src/client/tester/context.ts
index f498e89128a2..c040e323571b 100644
--- a/packages/browser/src/client/tester/context.ts
+++ b/packages/browser/src/client/tester/context.ts
@@ -15,7 +15,6 @@ import { convertElementToCssSelector, getBrowserState, getWorkerState } from '..
 
 // this file should not import anything directly, only types and utils
 
-const state = () => getWorkerState()
 // @ts-expect-error not typed global
 const provider = __vitest_browser_runner__.provider
 function filepath() {
@@ -222,8 +221,7 @@ function getTaskFullName(task: RunnerTask): string {
 }
 
 function processClickOptions(options_?: UserEventClickOptions) {
-  // only ui scales the iframe, so we need to adjust the position
-  if (!options_ || !state().config.browser.ui) {
+  if (!options_) {
     return options_
   }
   if (provider === 'playwright') {
@@ -250,8 +248,7 @@ function processClickOptions(options_?: UserEventClickOptions) {
 }
 
 function processHoverOptions(options_?: UserEventHoverOptions) {
-  // only ui scales the iframe, so we need to adjust the position
-  if (!options_ || !state().config.browser.ui) {
+  if (!options_) {
     return options_
   }
 
@@ -277,8 +274,7 @@ function processHoverOptions(options_?: UserEventHoverOptions) {
 }
 
 function processDragAndDropOptions(options_?: UserEventDragAndDropOptions) {
-  // only ui scales the iframe, so we need to adjust the position
-  if (!options_ || !state().config.browser.ui) {
+  if (!options_) {
     return options_
   }
   if (provider === 'playwright') {
@@ -336,11 +332,14 @@ function processPlaywrightPosition(position: { x: number; y: number }) {
 }
 
 function getIframeScale() {
-  const testerUi = window.parent.document.querySelector('#tester-ui') as HTMLElement | null
+  const testerUi = window.parent.document.querySelector(`iframe[data-vitest]`)?.parentElement
   if (!testerUi) {
     throw new Error(`Cannot find Tester element. This is a bug in Vitest. Please, open a new issue with reproduction.`)
   }
   const scaleAttribute = testerUi.getAttribute('data-scale')
+  if (scaleAttribute === null) {
+    return 1
+  }
   const scale = Number(scaleAttribute)
   if (Number.isNaN(scale)) {
     throw new TypeError(`Cannot parse scale value from Tester element (${scaleAttribute}). This is a bug in Vitest. Please, open a new issue with reproduction.`)
diff --git a/test/browser/fixtures/locators/blog.test.tsx b/test/browser/fixtures/locators/blog.test.tsx
index 991c0eacbf0e..41a6834dd4d6 100644
--- a/test/browser/fixtures/locators/blog.test.tsx
+++ b/test/browser/fixtures/locators/blog.test.tsx
@@ -18,6 +18,7 @@ test('renders blog posts', async () => {
 
   await expect.element(secondPost.getByRole('heading')).toHaveTextContent('qui est esse')
 
+  // TODO: click doesn't work on webdriverio when iframe is scaled
   await userEvent.click(secondPost.getByRole('button', { name: 'Delete' }))
 
   expect(screen.getByRole('listitem').all()).toHaveLength(3)
diff --git a/test/browser/fixtures/locators/vitest.config.ts b/test/browser/fixtures/locators/vitest.config.ts
index e32545f4ab22..a9652cc4257d 100644
--- a/test/browser/fixtures/locators/vitest.config.ts
+++ b/test/browser/fixtures/locators/vitest.config.ts
@@ -16,7 +16,6 @@ export default defineConfig({
       enabled: true,
       provider,
       name,
-      headless: true,
     },
     onConsoleLog(log) {
       if (log.includes('ReactDOMTestUtils.act')) {
diff --git a/test/browser/fixtures/viewport/basic.test.ts b/test/browser/fixtures/viewport/basic.test.ts
new file mode 100644
index 000000000000..56746956d933
--- /dev/null
+++ b/test/browser/fixtures/viewport/basic.test.ts
@@ -0,0 +1,58 @@
+import { page, userEvent, server } from "@vitest/browser/context";
+import { expect, test } from "vitest";
+
+test("drag and drop over large viewport", async () => {
+  // put boxes horizontally [1] [2] ... [30]
+  // then drag-and-drop from [1] to [30]
+
+  const wrapper = document.createElement("div");
+  wrapper.style.cssText = "display: flex; width: 3000px;";
+  document.body.appendChild(wrapper);
+
+  const events: { i: number; type: string }[] = [];
+
+  for (let i = 1; i <= 30; i++) {
+    const el = document.createElement("div");
+    el.textContent = `[${i}]`;
+    el.style.cssText = `
+      flex: none;
+      width: 100px;
+      height: 100px;
+      border: 1px solid black;
+      box-sizing: border-box;
+      display: flex;
+      justify-content: center;
+      align-items: center;
+    `;
+    el.draggable = true;
+    wrapper.append(el);
+
+    el.addEventListener("dragstart", (ev) => {
+      ev.dataTransfer.effectAllowed = "move";
+      events.push({ type: "dragstart", i });
+    });
+    el.addEventListener("dragover", (ev) => {
+      ev.preventDefault();
+      ev.dataTransfer.dropEffect = "move";
+      events.push({ type: "dragover", i });
+    });
+    el.addEventListener("drop", (ev) => {
+      ev.preventDefault();
+      events.push({ type: "drop", i });
+    });
+  }
+
+  // drag and drop only works reliably on playwright
+  if (server.provider !== 'playwright') {
+    return
+  }
+
+  await userEvent.dragAndDrop(page.getByText("[1]"), page.getByText("[30]"));
+
+  expect(events).toMatchObject(
+    expect.arrayContaining([
+      { type: "dragstart", i: 1 },
+      { type: "drop", i: 30 },
+    ]),
+  );
+});
diff --git a/test/browser/fixtures/viewport/vitest.config.ts b/test/browser/fixtures/viewport/vitest.config.ts
new file mode 100644
index 000000000000..403a56690a82
--- /dev/null
+++ b/test/browser/fixtures/viewport/vitest.config.ts
@@ -0,0 +1,21 @@
+import { fileURLToPath } from 'node:url'
+import { defineConfig } from 'vitest/config'
+
+// pnpm -C test/browser test-fixtures --root fixtures/viewport --browser.ui=false
+// pnpm -C test/browser test-fixtures --root fixtures/viewport --browser.headless=true
+
+const provider = process.env.PROVIDER || 'playwright'
+const name =
+  process.env.BROWSER || (provider === 'playwright' ? 'chromium' : 'chrome')
+
+export default defineConfig({
+  test: {
+    browser: {
+      enabled: true,
+      name,
+      provider,
+      viewport: { width: 3000, height: 400 }
+    },
+  },
+  cacheDir: fileURLToPath(new URL("./node_modules/.vite", import.meta.url)),
+})
diff --git a/test/browser/specs/runner.test.ts b/test/browser/specs/runner.test.ts
index 419aa61df9c4..78a746240713 100644
--- a/test/browser/specs/runner.test.ts
+++ b/test/browser/specs/runner.test.ts
@@ -10,11 +10,16 @@ describe('running browser tests', async () => {
   let passedTests: any[]
   let failedTests: any[]
 
+  beforeAll(() => {
+    const id = setInterval(() => console.log('[debug]', new Date().toISOString()), 2000)
+    return () => clearInterval(id)
+  })
+
   beforeAll(async () => {
     ({
       stderr,
       stdout,
-    } = await runBrowserTests())
+    } = await runBrowserTests(undefined, undefined, undefined, { std: 'inherit' }))
 
     const browserResult = await readFile('./browser.json', 'utf-8')
     browserResultJson = JSON.parse(browserResult)
diff --git a/test/browser/specs/utils.ts b/test/browser/specs/utils.ts
index 944d1492f61f..2e9ea19dfcbe 100644
--- a/test/browser/specs/utils.ts
+++ b/test/browser/specs/utils.ts
@@ -9,6 +9,7 @@ export async function runBrowserTests(
   config?: Omit<UserConfig, 'browser'> & { browser?: Partial<UserConfig['browser']> },
   include?: string[],
   viteOverrides?: Partial<ViteUserConfig>,
+  runnerOptions?: Parameters<typeof runVitest>[4],
 ) {
   return runVitest({
     watch: false,
@@ -18,5 +19,5 @@ export async function runBrowserTests(
       headless: browser !== 'safari',
       ...config?.browser,
     } as UserConfig['browser'],
-  }, include, 'test', viteOverrides)
+  }, include, 'test', viteOverrides, runnerOptions)
 }
diff --git a/test/browser/specs/viewport.test.ts b/test/browser/specs/viewport.test.ts
new file mode 100644
index 000000000000..e6daf48badd2
--- /dev/null
+++ b/test/browser/specs/viewport.test.ts
@@ -0,0 +1,19 @@
+import { expect, test } from 'vitest'
+import { runBrowserTests } from './utils'
+
+test('viewport', async () => {
+  const { stderr, ctx } = await runBrowserTests({
+    root: './fixtures/viewport',
+  })
+
+  expect(stderr).toBe('')
+  expect(
+    Object.fromEntries(
+      ctx.state.getFiles().map(f => [f.name, f.result.state]),
+    ),
+  ).toMatchInlineSnapshot(`
+    {
+      "basic.test.ts": "pass",
+    }
+  `)
+})
diff --git a/test/browser/test/userEvent.test.ts b/test/browser/test/userEvent.test.ts
index d4b43802b600..20b5ceec3a7e 100644
--- a/test/browser/test/userEvent.test.ts
+++ b/test/browser/test/userEvent.test.ts
@@ -135,9 +135,10 @@ describe('userEvent.click', () => {
       },
     })
 
+    // not exact due to scaling and rounding
     expect(spy).toHaveBeenCalledWith({
-      x: 200,
-      y: 150,
+      x: expect.closeTo(200, -1),
+      y: expect.closeTo(150, -1),
     })
   })
 })
diff --git a/test/browser/vitest.config.mts b/test/browser/vitest.config.mts
index b9f6ca89a18b..303f5fd77806 100644
--- a/test/browser/vitest.config.mts
+++ b/test/browser/vitest.config.mts
@@ -41,7 +41,7 @@ export default defineConfig({
       name: browser,
       headless: false,
       provider,
-      isolate: false,
+      // isolate: false,
       testerScripts: [
         {
           content: 'globalThis.__injected = []',