diff --git a/.changeset/fix-tray-keyboard-inset.md b/.changeset/fix-tray-keyboard-inset.md
new file mode 100644
index 00000000..ed4344d0
--- /dev/null
+++ b/.changeset/fix-tray-keyboard-inset.md
@@ -0,0 +1,5 @@
+---
+'@luke-ui/react': patch
+---
+
+Fix the mobile tray sitting behind the iOS on-screen keyboard.
diff --git a/packages/@luke-ui/react/src/combobox-field/combobox-field.browser.test.tsx b/packages/@luke-ui/react/src/combobox-field/combobox-field.browser.test.tsx
new file mode 100644
index 00000000..dc45df22
--- /dev/null
+++ b/packages/@luke-ui/react/src/combobox-field/combobox-field.browser.test.tsx
@@ -0,0 +1,71 @@
+import { afterEach, expect, test } from 'vite-plus/test';
+import { page, userEvent } from 'vite-plus/test/context';
+import {
+	comboboxTrayKeyboardInsetVar,
+	comboboxTrayViewportHeightVar,
+} from '../recipes/combobox.css.js';
+import { cleanupVisual, renderVisual } from '../test-utils/render-visual.js';
+import { ComboboxField } from './index.js';
+import { ComboboxItem } from './primitive/index.js';
+
+type CountryItem = {
+	id: string;
+	label: string;
+};
+
+const countryItems: Array<CountryItem> = [
+	{ id: 'au', label: 'Australia' },
+	{ id: 'ca', label: 'Canada' },
+];
+
+const renderCountryItem = (item: CountryItem) => <ComboboxItem>{item.label}</ComboboxItem>;
+
+const originalDescriptor = Object.getOwnPropertyDescriptor(window, 'visualViewport');
+
+afterEach(() => {
+	cleanupVisual();
+	if (originalDescriptor) {
+		Object.defineProperty(window, 'visualViewport', originalDescriptor);
+	} else {
+		// @ts-expect-error -- deleting a test-only own property
+		delete window.visualViewport;
+	}
+});
+
+test('sets the tray viewport height and keyboard inset custom properties from visualViewport', async () => {
+	const fake = Object.assign(new EventTarget(), {
+		height: window.innerHeight - 300,
+		offsetTop: 0,
+	});
+	Object.defineProperty(window, 'visualViewport', { configurable: true, value: fake });
+
+	renderVisual(
+		<ComboboxField
+			defaultItems={countryItems}
+			label="Country"
+			name="country"
+			placeholder="Select a country..."
+		>
+			{renderCountryItem}
+		</ComboboxField>,
+	);
+
+	await userEvent.click(page.getByRole('combobox', { name: 'Country' }));
+	await expect.element(page.getByRole('listbox')).toBeInTheDocument();
+
+	const popover = document.querySelector('[role="listbox"]')?.parentElement;
+	if (!popover) throw new Error('expected the listbox to have a popover parent');
+
+	expect(popover.style.getPropertyValue(comboboxTrayViewportHeightVar)).toBe(`${fake.height}px`);
+	expect(popover.style.getPropertyValue(comboboxTrayKeyboardInsetVar)).toBe(
+		`${window.innerHeight - fake.height}px`,
+	);
+
+	fake.height -= 100;
+	fake.dispatchEvent(new Event('resize'));
+
+	expect(popover.style.getPropertyValue(comboboxTrayViewportHeightVar)).toBe(`${fake.height}px`);
+	expect(popover.style.getPropertyValue(comboboxTrayKeyboardInsetVar)).toBe(
+		`${window.innerHeight - fake.height}px`,
+	);
+});
diff --git a/packages/@luke-ui/react/src/combobox-field/primitive/use-visual-viewport-vars.ts b/packages/@luke-ui/react/src/combobox-field/primitive/use-visual-viewport-vars.ts
index 0d387775..0d7b80c3 100644
--- a/packages/@luke-ui/react/src/combobox-field/primitive/use-visual-viewport-vars.ts
+++ b/packages/@luke-ui/react/src/combobox-field/primitive/use-visual-viewport-vars.ts
@@ -15,11 +15,25 @@ export function useVisualViewportVars(element: HTMLElement | null): void {
 		const trayElement = element;
 		const visualViewport = window.visualViewport;
 
+		// `innerHeight`/`clientHeight` don't reliably report the fixed-position containing
+		// block's height across browsers: on iOS Safari `innerHeight` tracks the visual
+		// viewport, so it shrinks with the keyboard and the old inset math collapsed to ~0.
+		// A probe pinned to all four edges via `inset: 0` measures that containing block
+		// directly, by construction, regardless of toolbar/keyboard state.
+		const probe = document.createElement('div');
+		probe.style.position = 'fixed';
+		probe.style.inset = '0';
+		probe.style.visibility = 'hidden';
+		probe.style.pointerEvents = 'none';
+		document.body.append(probe);
+
 		function update() {
 			trayElement.style.setProperty(comboboxTrayViewportHeightVar, `${visualViewport.height}px`);
+			// Read fresh each call in case the containing block itself changes (e.g. toolbar show/hide).
+			const probeHeight = probe.getBoundingClientRect().height;
 			const keyboardInset = Math.max(
 				0,
-				window.innerHeight - visualViewport.height - visualViewport.offsetTop,
+				probeHeight - visualViewport.offsetTop - visualViewport.height,
 			);
 			trayElement.style.setProperty(comboboxTrayKeyboardInsetVar, `${keyboardInset}px`);
 		}
@@ -33,6 +47,7 @@ export function useVisualViewportVars(element: HTMLElement | null): void {
 		return () => {
 			visualViewport.removeEventListener('resize', update);
 			visualViewport.removeEventListener('scroll', update);
+			probe.remove();
 		};
 	}, [element]);
 }