Does turning off Bluetooth affect GPS accuracy on a hike?

The short answer

No. Position on a recorded route comes from timing signals broadcast by GPS satellites, worked out entirely by the receiver chip. Bluetooth plays no part in that calculation, on or off, so turning it off before or during a hike leaves tracking accuracy exactly where it was.

That is a different answer from the one for Wi-Fi, which can give the very first fix a small head start where a network happens to be reachable. Bluetooth offers no equivalent shortcut. It is not a positioning system at all, and there is nothing about it for the receiver chip to lean on even briefly.

What Bluetooth is actually for

Bluetooth is a short-range radio, built to pair a phone with something close by — a pair of headphones, a watch, a car stereo — and keep a steady low-bandwidth connection to it. Its whole design points at devices sitting within a few metres, not at anything spread across a landscape the way GPS satellites or cell towers are. Nothing about the way Bluetooth works involves figuring out where the phone itself is; it is entirely occupied with talking to one or two paired accessories.

Why this is different from Wi-Fi

Wi-Fi and cellular data can genuinely speed up the first GPS fix, because a network connection lets the phone look up roughly where nearby access points and cell towers are known to be, and fetch satellite orbit data faster than picking it up cold from the sky — a shortcut covered in does turning off Wi-Fi affect GPS accuracy on a hike. That shortcut exists because Wi-Fi and cellular infrastructure are both spread out geographically, in a way a database can map. Bluetooth accessories are not spread out anywhere; a pair of headphones does not sit at a known, mappable location the way a cell tower does, so there is no equivalent lookup for Bluetooth to offer even in principle. It is not that the shortcut is switched off along with Bluetooth — it was never there.

What turning Bluetooth off actually changes

The real effect of switching Bluetooth off on a hike is entirely about accessories, not about the track. Paired headphones stop receiving audio, so spoken pace or distance announcements and any music playing have nowhere to go. A paired watch loses its connection to the phone. None of that touches the GPS receiver, which keeps listening to satellites and logging points at the same rate with Bluetooth on or off, the same way it keeps working with Wi-Fi off or in airplane mode.

Things that trip people up

• Assuming any radio on a phone must feed into GPS somehow — Bluetooth, Wi-Fi and cellular are three separate systems built for three different jobs, and only Wi-Fi and cellular have any role at all, and only in speeding up the first fix.
• Turning Bluetooth off mid-hike expecting a more accurate track afterwards — accuracy was never affected by Bluetooth being on, so there is nothing to gain.
• Losing spoken pace updates after switching Bluetooth off and assuming the app has stopped tracking — the recording is unaffected; only the paired headphones that were speaking the numbers aloud have gone quiet.
• Leaving Bluetooth on out of caution in case it "helps" GPS somewhere with no signal — it does not need to, since GPS never depended on it to begin with.

Where TrailCam fits in

TrailCam records a route from GPS in the background regardless of whether Bluetooth is on, off, or paired with anything. TrailCam can also speak distance and pace aloud as you walk, which does rely on Bluetooth when the audio is going to a pair of headphones rather than the phone speaker — that is the one part of a hike Bluetooth actually touches, and it has nothing to do with where the route itself gets recorded. TrailCam is free to download.