The Fi Mini ($189 for the hardware plus a 12-month cellular subscription) brings the location-tracking and data features of the Fi Series 3+ to a more compact design for smaller pets. This lightweight tracker—about half an ounce—can clip onto a variety of dog or cat collars. Even with its small size, battery life proved impressive in testing, lasting more than four weeks per charge. Though notifications were occasionally inconsistent, most escape alerts reached my phone within about two minutes of my puppy leaving the designated safe area, and the tracker provided speedy, reliable location updates in Lost Mode. With comprehensive location tracking, useful activity and sleep insights, and a polished mobile app, the Fi Mini earns our Editors' Choice award for GPS trackers for small pets.

Design: Lightweight Enough That My Bernedoodle Barely Noticed It

The Fi Mini measures 1.65 by 1.18 by 0.49 inches (HWD) and weighs 0.56 ounces, adding almost no weight to a collar. That's smaller and significantly lighter than the Fi Series 3+, which measures 3.2 by 1.18 by 0.45 inches and weighs 1.65 ounces.

(Credit: Tyler Hayes)

The tracker is all black, so it will be noticeable against lighter fur and hair. Importantly, the Mini is rated IP68 for water and dust resistance. The device comes with two simple rubber bands that let you secure it to any collar measuring 0.37 to 1.25 inches wide. The Series 3+ and older Series 3 trackers have an IP66K rating for protection against high-pressure water exposure, and include a collar with a stainless steel magnetic locking system that Fi says can withstand 500 pounds of pull force.

For this review, I enlisted the help of my mild-mannered 35-pound Bernedoodle, Mya, to wear the Fi Mini on her existing collar. My biggest concern about adding a tracking device around Mya’s neck was annoying her or creating disruption. After several weeks of uninterrupted use, she never pawed at it or tried to get it off. She’s easy-going, so picky pups might feel different, but I think the Fi Mini’s size is minimal enough for most small and medium-size dogs.

(Credit: Tyler Hayes)

Battery Life: Long-Lasting, But It Depends on How You Use It

According to Fi, the Mini offers up to six weeks of battery life per charge, depending on usage. The determining factor will be the amount of time the device spends connected to your home Wi-Fi versus the cellular radio. So, a dog’s daily routine and your location’s reception will come into play.

In my usage, the battery went from a full charge to 75% in 10 days. After 20 days of wear, it was down to 45%. At that point, I activated the Lost Mode for testing and pushed it a little harder than normal. So, I’m expecting to get close to the full six weeks during subsequent usage. If you want longer battery life, the company says adding a $39 Fi Base can extend longevity to up to three months, though the Mini can't charge on the Base like the Series 3/3+ can.

When you do need to recharge it, there’s a USB-C port. I didn’t find it hard to slide the Mini out of its charging rubber attachment for charging.

Subscription: Cellular Tracking Included

The Fi Mini costs $99 with a six-month Verizon cellular service subscription, or $189 for 12 months of service. At the yearly length, that comes out to $15.75 per month. If you want to save some money, you can opt for a two-year prepaid plan for $339 (about $14.15 per month). The hardware is included with the membership fee. For comparison, the Tractive Dog 6 costs $79 for the hardware, plus $10 per month for service.

The Fi subscription includes cellular connectivity, which enables live GPS tracking in Lost Mode. It also includes activity and sleep monitoring, 24/7 support, and unlimited replacements of the Mini if it’s damaged.

For peace of mind, Fi offers a one-month free trial. It'll send you a pre-owned device—you just pay shipping—so you can try the tracker and service for 30 days. This should alleviate any concerns about whether Verizon service is available in your area or about sizing.

Mobile App: Smart Features, But AI Still Feels Like a Work in Progress

The Fi mobile app (available for Android and iOS) is your hub for configuring the Mini and seeing all the data that the tracker collects. It's where you set your home boundary, monitor your pet's health stats, and see their current and past locations.

The app experience is polished and easy to navigate. Given the number of features and settings available, it doesn't look cluttered. I never found it confusing. Just be aware that by default, you could be inundated by the number of alerts the app sends. You'll want to go into the notification settings and look through all the options before it becomes annoying.

My biggest complaint about the Fi Mini is its minimum home boundary size. This isn't completely on Fi, but because of some of the technology’s limits, the safe area needed to be sized bigger than my property lines. Fi supports circular safe zones with a minimum radius of 60 feet or square/polygon-shaped boundaries of at least 11,309 square feet. I had to cheat by extending the boundary behind the backyard fence, where I knew Mya couldn’t get to. You’ll need to do this, too, if you live in an apartment or certain suburban homes.

Despite being a great experience, overall, there are two areas of the app I didn't care for: an integrated AI bot and a social feed, though both are easy to turn off.

AI is a buzzword, and Fi’s app is teeming with it. Actually, the company calls it Fi Intelligence, but you get the idea. Essentially, it’s an AI bot in front of your dog’s collected data. It lets you use natural language to dissect the data the Mini is collecting. You can ask questions like, "Is my dog sleeping enough?" and it will combine the dog's breed, age, and sleep data to provide an answer.

(Credit: Fi/PCMag)

For people with constant questions about their pet or the data they're seeing, this might be compelling. I found it to be forgettable and mostly uninteresting right now. That’s not to say it won’t grow in usefulness, but, for me, it was only a mild curiosity. I could only come up with a few questions to test the feature, so I would like to see it become more proactive.

While the AI aspect of the mobile app doesn't appeal to me, it's implemented in a way that doesn't take over the interface, which I appreciate.

Escape Alerts: Most Arrived Within Two Minutes

(Credit: Fi/PCMag)

The main reason to get a GPS pet collar is for location tracking. The Fi Mini performs very well in this regard. I tested the response time daily for over four weeks, each time my wife took Mya out for a walk. In testing, alerts about Mya leaving the safe zone arrived on my phone within one to nine minutes. Most of them were around two minutes, and the nine-minute delay occurred only once.

That's faster overall than the Fi Series 3, which took an average of three to five minutes to deliver an escape alert after a dog exited the safe zone. While we haven't tested Tractive's Dog 6 device, an earlier version offered some of the fastest escape alert times for the category, with notifications typically arriving within one minute.

If someone else is added to the account as a pet parent, the Fi Mini is smart enough to know when either person is connected to the device, even if they leave the safe zone. So, for example, when my wife took the dog on a walk, I wasn’t alerted when they left the safe zone once I added my wife to the account. 

However, the app still sent me recaps of the walk after they returned. If I opened the app while they were gone, I was able to see their approximate location. While they were gone, I would occasionally turn on Lost Mode, and I could instantly see Mya’s location.

You can see heat maps for places the tracker has been. This could be helpful if you want to show someone where you like to walk. I also liked looking back over past walks in the timeline view. This will replay the walk with a dot moving along the map. Again, it could be helpful in some cases, or just a way to jog your memory of past routes.

Health and Sleep Tracking: Accurate for the Metrics That Matter Most

Most people will want the Fi Mini to provide peace of mind around a pet’s location, but it also tracks health, offering insights into rest, activity (steps), barking, eating, drinking, licking, and scratching.

(Credit: Fi/PCMag)

For Mya, the rest and activity stats were relatively accurate. Her play time, walks, and general cruising around the backyard seemed to match what the app showed. The other health areas seemed less accurate. Specifically, the eating and drinking were way off. Since Mya doesn’t bark much, that area was less meaningful in my tracking of her stats.

While I wouldn’t buy the Fi Mini for its health tracking, I still found it interesting as a bonus feature alongside the location tracking. The rest and activity are probably the most important, and those were the most accurate of the bunch.