iPhone Duo Touch ID: Rest your finger to open it directly

This article may contain affiliate links. Learn more on our Partner Program page.

On iPhone Duo, Touch ID is built into the side button. With one setting, simply resting your finger on the button opens the iPhone directly. You can check whether it is already turned on in two places in Settings.

iPhone Duo is the first new iPhone with a fingerprint sensor since the iPhone SE (3rd generation) from 2022. Instead of Face ID, Touch ID sits in the side button, as Apple describes in the iPhone Duo technical specifications. According to reports, Apple is only testing Face ID in prototypes for an iPhone Duo 2.

The feature is familiar from iPads with Touch ID in the top button. Apple describes it in the support document Use Touch ID on iPhone and iPad under the name "Rest Finger to Open." On iPhone Duo, the switch has the same name, as I checked on my own device. All other details about the device are on the iPhone Duo fact page.

Key Facts at a Glance

• "Rest Finger to Open" opens iPhone Duo with Touch ID as soon as the enrolled finger rests on the side button.
• If the setting is off, Touch ID only unlocks the device, and you still have to swipe up afterward.
• On my iPhone Duo, it was already turned on after setup – a quick look in Settings will tell you for sure.
• The switch is located under Accessibility › Side Button and also under Touch ID & Passcode.
• Both switches control the same setting: flip one, and the other flips too.
• A fingerprint must be set up first.

What the setting does

Apple describes the feature directly below the switch: "Open iPhone with Touch ID by resting your finger on the side button." When the enrolled finger rests on the button, Touch ID recognizes the fingerprint, and the iPhone opens without any further step. On my iPhone Duo, the switch was already turned on after setup.

If the switch is off, Touch ID still unlocks the device, but it stays on the Lock Screen. It only continues once you swipe up. The two methods below show whether the switch is on or off on your own device.

Method 1: Via Accessibility

Here's how to turn the feature on or off via Accessibility:

1. Open Settings and tap "Accessibility."
2. Scroll to the "Physical and Motor" section and tap "Side Button."
3. "Rest Finger to Open" is at the very bottom of the page. Flip the switch.

The same page also lets you adjust the click speed for double- and triple-clicks and choose what happens when you press and hold the side button – the options are Siri, Classic Voice Control or "Off."

Method 2: Via Touch ID & Passcode

The same switch also appears where fingerprints are managed:

1. Open Settings and tap "Touch ID & Passcode."
2. Enter your passcode.
3. "Rest Finger to Open" is below the list of fingerprints. Flip the switch.

It doesn't matter which method you use. On iPhone Duo, I checked both switches against each other: when one is flipped, the other changes with it – both when turning it on and when turning it off. So it is a single setting that Apple offers in two places.

Set up a fingerprint first

Without an enrolled finger, the switch has no effect. Fingerprints are added under "Touch ID & Passcode" with "Add a Fingerprint." Apple recommends holding the device the way you normally would when unlocking it.

Because iPhone Duo is held differently when folded and unfolded, it can make sense to enroll more than one finger. According to Apple, up to five fingerprints are possible, although each additional one can slightly slow down recognition.

Why I keep the setting turned on

I think "Rest Finger to Open" is the better choice on iPhone Duo. Touch ID already recognizes the finger as soon as it rests on the button, and I see no security benefit in the swipe afterward – in both cases, the device is only unlocked with the enrolled finger.

However, if you often pick up the device with your finger on the side button while the display is on, you will open the iPhone even when you only wanted to glance at the Lock Screen. In that case, turning the switch off is the better setting. More articles about the foldable iPhone are collected on the iPhone Duo topic page.

iPhone Duo Touch ID – the key points at a glance

With "Rest Finger to Open," iPhone Duo opens directly as soon as the enrolled finger rests on the side button – without the setting, you still have to swipe up after unlocking. The switch is located under Accessibility › Side Button and under Touch ID & Passcode, and both control the same setting. On my device, it was turned on from the start – a look at either of the two places will tell you for sure on your own iPhone Duo.

Do you keep the switch turned on on your iPhone Duo, or do you prefer to swipe up yourself after the fingerprint? Tell us in the comments which finger you rest on the side button – folded and unfolded.

Frequently asked questions: iPhone Duo Touch ID