Does Guided Access affect GPS tracking on iPhone?

The short answer

No. Guided Access is a screen-and-button lock — it decides which app stays on screen, which gestures and hardware buttons still work, and whether specific parts of the display respond to a touch at all. It has no connection to background location permission, which is what actually lets a recording app keep tracking position while nobody is looking at the phone. A hike already being recorded when Guided Access starts keeps recording exactly the same way once the session begins, and the track it produces looks no different for having had Guided Access running over it.

What Guided Access actually locks down

Guided Access lives under Settings > Accessibility, and turning it on adds a way to start a session: triple-click the side button — the Home button, on an iPhone that still has one — while the app you want locked in is the one open on screen. From that moment, the phone stops offering any way out of that single app on its own: swiping up to the home screen does nothing, the app switcher does not open, and Control Center is not reachable by a swipe either. Ending the session again asks for the device passcode, or Face ID if that is set up as the way out, before anything else on the phone becomes reachable again.

Before a session starts, an Options screen offers a few more levers: the volume buttons and the side button can each be switched off individually, motion-based input can be ignored, and — the one hikers tend to find most useful — one or more zones can be circled directly on the screen, so a touch landing inside that zone does nothing at all while the rest of the screen keeps responding normally.

Why none of that reaches a GPS recording

Background location is granted once, the first time an app asks for it, and iOS hands out location updates to that app afterward through a completely separate system from anything Guided Access touches. Guided Access works entirely at the level of what a touch, a button press or a gesture is allowed to do on the screen currently showing — it has no setting, and no reason to have one, that reaches down into which apps are allowed to keep receiving GPS updates in the background. A recording that already had permission to track with the screen off keeps that permission through a Guided Access session the same way it keeps it through anything else that changes what is visible on screen, because visibility and permission were never the same thing to begin with.

The screen itself still behaves the way it always did, too. Locking out the Sleep/Wake button under Guided Access only removes your own ability to press it — the phone's ordinary Auto-Lock timer keeps running underneath and still turns the display off on its usual schedule, which is a separate question from whether a recording keeps going with the screen dark, already settled by how background recording works in general.

The actual reason to reach for it on a hike

Guided Access was built for a different situation — handing a phone to a child, or to someone who does better with a single task staying in front of them — but the same lock does something genuinely useful in a hip pocket or a hand that brushes against a trekking pole strap. A phone recording a hike from inside a pocket takes the occasional accidental touch through fabric, and without anything stopping it, that touch can land on the app switcher, on Control Center, or on a button inside the recording app itself — pause, stop, delete. A Guided Access session removes every one of those accidental targets except the one app you locked it to, and circling off a zone around anything inside that app you would not want a stray tap to reach closes the last gap.

Things that trip people up

• Starting a session without a passcode set up, or without remembering it — ending Guided Access needs the device passcode or Face ID, with no other way out, which matters more once a phone is locked to one app for an entire day on the trail.
• Circling off a zone that happens to cover the button used to capture a photo, a clip or a voice note — the zone blocks touch evenly, with no sense of which button underneath it matters to you.
• Assuming the Sleep/Wake button being disabled means the screen stays on indefinitely — Auto-Lock keeps dimming and locking the display on its own schedule regardless, and turning that off is a separate setting entirely.
• Expecting Guided Access to change GPS accuracy, GPS battery use, or how often a position gets logged — none of those are things a screen lock has any way to touch.

Where TrailCam fits in

TrailCam records a route with GPS in the background regardless of what is happening on screen, so a Guided Access session pinned to TrailCam changes nothing about how the track gets recorded — the app was already going to keep tracking with the screen off, locked, or showing something else, long before Guided Access became part of the picture. A photo, a video clip or a voice note pinned to a point on the route still captures normally through a session, too, as long as the button used to capture it was not one of the zones deliberately blocked off. The app is free to download.