How to lock your iPhone before handing it to a toddler

The situation is always the same. You need ten minutes, the phone is the only thing that will buy them, and the last time you handed it over they sent a voice note to your boss. Here's the order of operations, from the version you can do right now at the table to the version worth setting up once.

The thirty-second version

Open whatever app they're going to use. Triple-click the side button to start Guided Access — turn it on first in Settings › Accessibility › Guided Access and give it a passcode. The phone is now stuck in that app. While you're there, turn on Do Not Disturb so incoming messages don't appear, and turn off Lock Screen notification previews if you haven't already. That covers most of the risk in under a minute.

The setting to change before it costs you money

Settings › Screen Time › Content & Privacy Restrictions › iTunes & App Store Purchases. Set In-app Purchases to Don't Allow, and Installing Apps to Don't Allow. Do this once and leave it. Note that Ask to Buy — the approval flow people often suggest — only applies to a child with their own Apple Account in your family group, so it does nothing when the child is using your phone. This is the setting that actually applies to a handover.

Set a Screen Time passcode, separately from your device passcode

In Settings › Screen Time › Lock Screen Time Settings, set a four-digit code that is not your phone passcode and that your child has never watched you type. Everything else here rests on this. Without it, an older child can open Settings and switch off every restriction you've set, including ones placed by a third-party app. Use a recovery Apple Account when it offers, because this code is genuinely difficult to reset otherwise.

Trim the Always Allowed list

Settings › Screen Time › Always Allowed controls what stays reachable no matter what. By default that includes Messages and FaceTime — remove them unless you want them available. Phone can't be removed, deliberately, so emergency calls always work. Knowing this list exists explains an otherwise baffling experience: you locked everything down and your child still got into Messages.

The version worth setting up once

If this happens more than occasionally, a one-tap mode beats reconfiguring every time. Reef lets you build a profile — pick the apps that stay usable, add kid-safe websites as tiles, and it comes with five offline games with no ads and no links out. Tap Start and everything else is shielded; Face ID or a PIN gets you back out. One profile is free, and the shield, PIN and passcode recovery are never paywalled. Make a 'Restaurant' profile and a 'Car' one and you're choosing from a list instead of setting things up.

iOS behaviour described here was checked against iOS 26. Apple moves settings between releases — if a path doesn't match what you see, the feature is usually still there under a nearby name.