Chill-Dogs
Fi Dog Collar Review
Cellular GPS tracking for everyday dogs — city walks, parks, travel. Here's what it does well, what it costs, and where it stops working.
What Fi Is
Fi is a GPS dog collar that uses the LTE cellular network to report your dog's real-time location to a companion app. The collar includes a built-in GPS chip, an LTE radio, and a step counter. It's designed to work like a fitness tracker for dogs, with the safety layer of real-time location.
The Series 3+ is the current generation. It's slimmer and lighter than previous versions, with improved battery life and waterproofing. The core value proposition: if your dog gets loose in a city, suburb, or area with LTE coverage, you'll know where they are in near-real-time and get an alert the moment they leave a designated safe zone.
Fi is a good product. The key is understanding what it is: a cellular tracker. It works where cell service works. It doesn't work where cell service doesn't work. That distinction matters.
How Fi Works
LTE Cellular Tracking
Fi connects to the nationwide LTE network (same towers your phone uses) and reports GPS coordinates to the app. Updates happen continuously when the dog is moving. No WiFi or home network required — just cell coverage.
Geofence Safe Zones
Set home, work, dog park — any location as a safe zone. The moment your dog leaves the zone boundary, you get a push notification. This escape-alert feature is the primary safety value for most owners.
Live Tracking Mode
When an escape alert fires, you can activate live tracking to follow your dog's movement in near-real-time on the map. Updates increase in frequency during active tracking. This drains the battery faster.
Activity + Steps
Fi tracks daily steps, activity minutes, and sleep. You can set step goals and see trends over time. Compared to competitors, the activity data is detailed and easy to read in the app.
Subscription Model
LTE access requires a monthly or annual subscription. Without it, you lose real-time tracking — the collar reverts to step counting only. Factor the ongoing cost into your decision. Monthly plans are more expensive; annual plans offer a discount.
IP68 Waterproof
Rated for swimming and full submersion. Handles rain, mud, beach, and river crossings. The charging dock is magnetic — you don't need to remove the collar for everyday charging.
Pros & Cons
What Fi does well
- Real-time location on LTE nationwide network
- Escape alerts and safe-zone geofencing
- Slim, lightweight, IP68 waterproof
- Step counting and activity data included
- 12-month membership included — best per-month value
Trade-offs to know
- Requires cell signal — unreliable in remote or no-service areas
- Ongoing subscription after first year
- Battery life shorter in heavy-tracking mode
Best For
Fi is a strong fit for a specific kind of dog and owner.
Includes 12-month membership — best per-month value for Fi
City and suburban dogs
Where LTE is reliable and escape alerts are the primary concern, for example, if you mistakenly leave your yard gate open.
Dogs who travel to parks, campgrounds, and popular trails
Most well-visited parks and campgrounds have LTE coverage. Verify your specific destination — Fi works in more places than you might expect.
Owners who want health + activity data bundled
If you want step tracking, sleep monitoring, and location in one device, Fi provides all three.
Dogs who hike into remote or wilderness terrain
Fi stops working the moment you leave cell coverage. For backcountry use, you need a Garmin off-grid system instead — or in addition to Fi for city use.
Hunting or working dogs in rural terrain
Rural coverage is inconsistent. Garmin off-grid systems are the standard in this use case for good reason — they work everywhere with no subscription.
Stunt Puppy Fi-Ready Collar
A collar designed to work with Fi Series 3 and 3+ devices
Where Fi Falls Short
The primary limitation isn't a design flaw; it's the nature of cellular technology. LTE only works where cellular towers exist. In remote terrain, mountains, canyons, or rural areas outside network coverage, Fi cannot report location. The collar continues to record steps (passively), but live tracking is unavailable.
A real example: during the Cerro San Luis Obispo hike, Rhys wore a Fi collar. The summit had no LTE signal. The app showed the last known location as the trailhead parking lot — data from before the ascent. When Rhys ran into the fog, the collar was unable to pinpoint his location. Not because it malfunctioned, but because it was the wrong tool for that environment.
Planning a backcountry hike?
Check cell coverage maps (T-Mobile, AT&T, Verizon) for your specific trail before departing. Many popular hiking destinations lose coverage on the ascent before the summit. If coverage is uncertain, consider adding a Garmin off-grid system for the trip.
See Garmin off-grid systems →Compare Fi against all tracker types side by side:
Full GPS Tracker Comparison →Fi Collar FAQ
- Does Fi collar work without WiFi?
- Fi uses LTE cellular, not WiFi. It works anywhere with LTE signal — no home network required. However, without LTE signal (in remote wilderness, mountains, or dead zones) the collar cannot report location.
- Does the Fi collar require a subscription?
- Yes. Fi requires a monthly or annual subscription to access the LTE tracking network. The collar hardware is purchased separately. Without a subscription, you lose real-time tracking.
- How accurate is Fi GPS tracking?
- Fi GPS accuracy is typically within 10–30 feet under open sky. Accuracy can reduce in dense urban canyons, heavy tree cover, or areas with GPS interference. Real-time updates generally happen every few seconds when the dog is moving.
- Is Fi waterproof?
- The Fi Series 3+ collar is rated IP68 waterproof. It handles rain, mud, and swimming. This is one of the practical advantages of Fi over some competing cellular trackers.
- How long does the Fi battery last?
- Battery life varies significantly by tracking mode. In standard mode with moderate use, Fi claims its battery lasts up to 3 months. In heavy real-time tracking mode (continuous updates), the battery depletes much faster — often within a few days. Actual battery life depends heavily on how actively the location is being polled.
- Can I use the Fi collar for hiking?
- Fi works on hiking trails that have LTE coverage, which includes most popular trails near populated areas. It does not work in true wilderness, backcountry, or remote mountains without cell signal. Before taking Fi on a hiking trip, check the cell coverage map for your specific trail.