Do GPS dog trackers work without cell service?

Every tracker we cover does two jobs. It works out where your dog is using satellites, and it sends that location to your phone over a cellular network. The first job works almost anywhere outdoors. The second needs a signal. So the real question is what happens when the signal drops.

What each tracker does without a signal

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Your phone's signal isn't the tracker's signal

Most trackers use LTE-M, a low-power cellular network built for devices. Three things make it different from the bars on your phone:

• The tracker picks its own carrier. Fi's Series 3+ uses AT&T no matter which carrier your phone uses.
• LTE-M can reach further. It's designed for extended coverage, and AT&T says it reaches deep inside buildings and even underground.
• It has its own maps. Carriers publish separate coverage maps for these device networks.

So a spot where your phone struggles may still work for a tracker, and the reverse can happen too. Check the tracker's network, not your own.

How to check coverage before you buy

1. Use the brand's own tools. Tractive's product page has a coverage checker for your address. Fi's help center links the carrier maps for each of its trackers.
2. Look at the carrier's device map. T-Mobile publishes a Cat-M (LTE-M) map you can search by address. AT&T links its LTE-M map from its business site.
3. Check the FCC map for a rough picture. The FCC National Broadband Map shows each carrier's reported 4G and 5G coverage outdoors. It doesn't show LTE-M or indoor coverage, so treat it as a guide.
4. Test it during the return window. Walk the edges of your property and the trails your dog uses with the tracker in live mode. Fi recommends testing Lost Mode as soon as your tracker arrives.

If you live where the signal is spotty

If you need to keep your dog in, pick a fence collar that works offline. Halo stores your fences on the collar, and SpotOn's fence runs on satellites alone with no plan needed. SpotOn's site describes its containment as working anywhere the collar can see the sky. See Halo vs SpotOn.

If you need to find your dog, pick the tracker whose network covers the places your dog goes, and set up home Wi-Fi or a base station so the battery lasts. Fi also sells the Fi Ultra, which adds a satellite connection through T-Mobile's T-Satellite with Starlink for places with no cell signal at all. It's US-only, costs $299 and lasts 2–3 days per charge.

Trees, hills and buildings

Coverage isn't the only thing that changes in the country. GPS needs a view of the sky, and thick tree cover, deep ravines and metal buildings can make locations drift. Halo notes that trees and buildings degrade GPS accuracy, and SpotOn offers a Forest Mode for wooded properties. Tractive owners report the same drift in heavy woods. Expect the dot on the map to wander a little under trees.

Questions people ask