Fi Dog Collar Review: A GPS Dog Collar For Active Dogs
Series 3 Fi Dog Collar review covering battery, sleep tracking, using GPS to track your dog and more, based on two years of usage traveling, hiking & at home.
Updated JULY 17 2025: The Fi Dog Collar Series 3 is a GPS smart collar for your dog, which uses a combination of Wi-Fi and GPS to track your dog’s location, as well as tracking the number of steps your dog has taken in the day, and It also offers dog sleep tracking.
Perhaps obvious once you think about it, the ‘Fi’ in Fi Dog Collar is pronounced the same as the Fi in ‘Fido’ or Wi-Fi.
For this Fi Collar review, I have worn all three versions of the Fi Collar over more than three years, including the newest Fi Collar, the Series 3 (featured in this review), and the previous version, the Fi Collar Series 2.
I've included a comparison to the Fi Series 2 in this Fi Series 3 review, too, in case you're familiar with the Series 2 and wondering how the new version compares.
Keep reading this Fi Dog Collar review to find out what I (and my humans) think about using this GPS Fi Smart Dog Collar in real-world, everyday scenarios.
If you purchase through links in this article, we may earn a small affiliate commission. For exclusive content, our free newsletter, and more perks become a member, (it's free!). -The Trail & Kale team ✌🏼
How does the Fi Dog Tracker Collar work?
This GPS Dog Collar uses the AT&T network for locating your dog when he or she is out of the house alone (or if they escape the bounds of your home), as well as Wi-Fi and Bluetooth-based safe zones (also known as an invisible fence collar or a GPS dog fence), which would typically include:
- Your home - where your dog's Fi Collar base station should be plugged in and connected to Wi-Fi. This creates a WiFi Geofence for your dog.
- Proximity to you - or more specifically, within Bluetooth range of your phone. This creates a Bluetooth dog fence relative to your smartphone. When your dog steps outside the range of bluetooth, the Fi Collar switches to tracking your dog with GPS.
- Custom Safe Zone/GPS Dog Fence - You can set custom radial GPS dog fences in any location you like, using the Fi dog collar App. So this is the geofence you would use if you were at a friend's house, or camping for example, where there's no GPS base station, and your pup could potentially wander off, away from your parent's smart phone.
- As needed, additional base locations (such as your office, or dog sitter/parents' home), and the phones of other trusted people, such as your dog walker, friend, spouse, kid, etc.
This isn't just a GPS dog tracker however, it can also track the number of steps your dog takes throughout the day, and then compare your dog's activity to other Fi Dog Collar users around the USA.
I love this leaderboard feature as it's a great motivator for my human parents to take me out on more walks and trail runs.
Oh speaking of trail running, you totally need to go trail running with your pup, this trail running with your dog guide shares everything you need to know about how to take them for the first time, and beyond! If you're not a trail runner yourself but would like to know more, read our beginner's guide to trail running (for humans).
The Fi collar also tracks my sleep quality too! Now my parents know all about my 'running in my sleep' habits! Gots to stay fit!
Trail Running With Your Dog [2026 Guide]
Real-world advice for trail running with your dog: in this post we share everything we wish we knew when we were new to running with our own adventure dog.
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What is the Fi Dog Collar made from?
The Fi Dog Collar has a nice, solid construction to it. It’s definitely a lot heavier than my regular webbing collar, as it has a matchbox-sized small GPS unit and durable metal hardware, including a quick-release buckle and loop for dog tags and leash attachment.
My favorite dog running leash connects very nicely to it.
Fi state that their collar is chew-proof and generally dog-proof - and it comes with a 1-year warranty, which is reassuring.
The Fi Series 3 unit has a full stainless steel body frame, which apparently allows for more than 400lbs of static force (which is much more than previous versions, by the way). This is a LOT of strength, designed to withstand even the most boisterous of dogs (yes, including me, I'm pretty dang strong, ya know).
I’ve worn mine pretty much every day for the last couple of months and it has picked up a few light scratches as you can just about see in the photos, and I’m sure it will pick up a few more as I spend more time on the trails and nosing into brambles, that sort of thing.
One thing to be mindful of is if you have long, metal dog tags attached to the D-ring that they might hit the GPS unit when you run or shake off, so if that's a concern, I suggest getting soft tags, a tag silencer, or a jingle-free tag that attaches to the collar strap rather than the D-ring.
If you do damage your Fi dog tracking collar’s fabric, or you want to change the color, you can buy a replacement nylon webbing Fi collar band for less than $30.
Alternatively, you can also get creative and put your Fi tracker on other brands of dog collar.
I didn’t start wearing my Fi GPS dog tracker until I had grown to 30lb and was a 4+ month-old pup, as my parents didn’t want me wearing a heavier collar when I was younger and smaller.
I was more of a baby dog at that point so I wasn’t able to go out on as many adventures as I do now.
Is the Fi Dog Tracker waterproof?
Yes! If you’re going to invest in a Fi collar dog GPS tracker and pay a lot more than a regular dog collar to buy one, then you definitely need it to be waterproof and stand up to not just rain but your dog jumping into ponds, lakes, puddles, etc etc.
I've tried drowning it in a lake when my humans took me stand-up paddleboarding, but haven't been able to.
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The Fi Series 3 is highly waterproof and has an IP68 and IP66 rating, which are the highest waterproof standards available and mean it's been tested for water pressure and submersion, not just splashes and rain. Perfect for adventurous dogs!
It's my personal preference but I prefer to have my baths naked, so I haven't tried it in the bath, but if the Fi collar folks say it's waterproof, then I guess you could have a bath with it on, too...
...but why would you feel the need to, unless you hate baths so much that you may escape from home mid-bath?).
How long does the battery last on the Fi GPS Dog Collar?
One of the outstanding features of the Fi Dog Collar is that the battery can last up to three months between charges.
The three months battery life is based on if your collar does not spend much time outside of the range of your home base station, i.e. you don't get out much.
The length of time the Fi collar's battery lasts naturally depends on how active a dog you are and how much time you spend out of the range of the house base station.
When outside the range of your base station's wifi, the GPS dog collar requires more battery power when connecting to your parent's/dog-walkers phone via Bluetooth.
So you should expect the battery to run down more quickly if you spend a lot of time away from your home wifi and parent's phone.
This is the same story when it's picking up GPS signal when out of range of their phone and your home base (if you have a Fi subscription to effectively turn your Fi Dog Tracker into its own mobile device - more on that, later).
As a Border Collie, and therefore by definition one of the most active dog breeds, I do drain the battery quicker than the stated three months maximum battery life, and my parents charge it after around 8 weeks.
It gets charged more frequently if we are out traveling for long periods on a road trip in our campervan, for example. This is because it's not on wifi so the battery drains down quicker.
They get notified when it has 20% or less battery, so there's plenty of time for them to remember to charge it before it gets very low, and they normally charge it at night when I'm safe and sound in my bedroom.
8 weeks for a collar worn by a busy dog doing 2-3 walks a day (and/or running and frisbee sessions) is a long time to go between charges (especially when considering my parents have to charge their smartwatches pretty much daily!).
What is a 'safe zone' for the Fi Dog Collar?
The Fi Smart Dog Collar comes with a Fi Base, which is also used to charge the Fi collar.
Safe zones are defined by a perimeter range around the Fi Base, as well as when the collar is away from home but within Bluetooth range of a designated owner/dog-walker.
Having the home safe-zone being designated by the Base location helps save on battery life as the Fi collar dog GPS tracker doesn’t need to pick up and track from GPS when it knows it’s within range of the base station, which is a neat feature.
You set up the Base and the designated humans using the Fi app. Designated humans may include family members, your dog walker, and anyone else who may be alone with your dog.
Designated humans need to have their phone with them and the Fi app installed for this to work. The app also needs to be open and running in the background on their phone.
If your dog is near one of your designated owners/walkers when out of the house, then you can get notified via the Fi app notification and/or a text message when they leave the safe (home) zone for a walk with that person.
For example, the message my parents receive when my Dad takes me out for a walk is ‘Kepler just left home with Alastair’.
If I was to leave home without someone my parents have set up in the Fi app, or if the person walking me does not have their phone with them, the message my parents receive will just say ‘Kepler just left home’.
This also happens if someone doesn't have the Fi app open in the background on their phone to help the collar connect via Bluetooth when out of range of the base station - so the collar doesn't know the dog is near an owner/walker.
If you receive a notification like this, and you know your dog should not be out on a walk somewhere, then this may be the trigger you need to set off the ‘Lost Dog Mode’ and start tracking down the sneaky canine if they’ve escaped home.
For me, the message comes through within around a minute of leaving the house - I have to be outside of the safe-zone perimeter, which extends beyond our front door (as our current home is not large) so there is sometimes a lag between me leaving the front door and triggering the notifications that I have left home.
It’s also worth noting that your dog is frequently at another location (such as a friend or family members', pet sitters', office, etc.) it may be helpful to have an additional Fi Base (currently $39) to avoid having to transport your home Fi Base and reconfigure wifi to each location.
Also, if you have a large house/property then you may also benefit from having more than one base station (assuming each base station can connect to a wifi network - i.e. you can’t get one to have at the end of the garden if that’s out of range of your Wi-Fi).
How does the Fi Collar dog GPS tracker ‘Lost Dog Mode’ work?
If you activate Fi Collar's ‘Lost Dog Mode’ using your Fi app, then this turns on live location tracking on your dog’s collar to help find him or her.
NOTE:you need to have a Fi subscription so that your Fi GPS Collar acts as its own cell phone, to enable the Fi collar to be tracked using GPS when your dog is not near to an owner's phone. When you buy a Fi Series 3, you're essentially buying that subscription and you can choose different subscription lengths (see pricing details later in this review).
Lost Dog Mode also activates a red pulsing light on your dog’s Fi collar to help make them easier to spot in the dark, and sends a location notification to you every minute so you can track them down.
When we tested it (by having my Mom take me out without her phone, so it looked like I had taken myself for a walk), the GPS was accurate to within around 50ft or so. This was a fun game of ‘find me’, but it could save my life if I was to escape.
I expect the accuracy would vary depending on how strong and reliable the cell service is in a location where your dog goes missing, but I would hope that it gets my parents close enough to me that they can either see me at a distance and/or call me back to them.
It’s also worth noting that because the Fi collar dog GPS tracker relies on me being within cell service, it won’t be able to track my location in an area without a phone signal.
When in Lost Dog Mode, the battery life of the Fi collar dog GPS tracker is up to two days, as it’s using GPS signals to refresh the location status every minute, which consumes a lot more battery juice than regular use.
With the Fi Series 3 collar, the 'lost dog mode' features live tracking. So the map and information in your Fi app should constantly update for your dog's location, similar to how you'd track a friend with an Apple device using 'Find my Friends'. This is a significant upgrade from the Series 2's lost dog mode, which updated every 60 seconds rather than on a more frequent 'live' basis!
Does the Fi Dog Collar dog tracking device have a light?
Yes! One feature that my parents love is that at the push of a button on the Fi app, my Fi collar lights up with a pulsing light. You can choose from 7 different colors including blue, pink, yellow, and green.
It’s just one part of the Fi collar so not anything super-bright or flashy, but it’s a nice feature for night walks, especially if it’s very dark where you are, you’re near an area with cars or other people, and you’re a dark-colored dog who is harder to see.
Speaking of night walks, if you're in need of a dog collar light or reflective dog gear to help them be seen when walking in the dark, check out our reflective dog gear buyer's guide.
Activity Tracker for Dogs: Using the Fi GPS smart dog Collar to track your dog's steps
A nice feature of the Fi Smart Dog Collar is that it’s not just a dog GPS tracker to find your dog's location.
My Fi collar dog GPS tracker also counts my steps and summarizes how many steps I did on each walk (or run).
This way, my humans can use the app to set a daily step goal for me and track my daily step activity in the Fi app.
I gather there is no proven science specifying what is a ‘healthy’ amount of steps for a dog, and of course, that would vary between dogs’ individual needs.
But it’s a nice feature, and like a human’s smartwatch step tracker, can be used as a prompt to make sure that if you’ve had a quiet few days and not taken your pup out for as much activity as normal, you may want to step it up.
Speaking of stepping it up... have you heard that it's possible to get a treadmill for your dog? Great for those freezing winter days when you still want to get your workout in!
The Fi 'Strain Score'
Equally, and importantly for a growing boy such as myself, the goal can also be used as a target to stay BELOW - ie. So that I don’t get too much exercise, as I need to make sure I don’t over-use my growing puppy body and risk an injury.
Before Fi introduced the Strain Score in June 2022, my parents used my steps data and general common sense to help ensure I was getting enough rest and not being too busy or working out too much.
But now, the Strain Score actually gives you more information on this, by comparing your dog's activity compared to their average, as well as other Fi dogs. It's a measure of activity, relative to rest and sleep.
The information can be found if you scroll down within the 'activity' view screen.
Here's what my Strain Score looks like from yesterday. I had a chilled morning but then got to run around my backyard with a frisbee while my Mom did some gardening in the afternoon... but stayed within the average range of similar Fi dogs' activity levels.
This is a really cool feature and a step towards the Fi device helping track dogs' health and recovery status from exercise in a similar way to my parents' favorite human GPS watches do [more on those, here: The Best GPS Watches For Running & Hiking].
Fi dog breed ranking
One nice feature that my parents find entertaining is the ranking by breed, which tracks the last month of steps and compares you to how other dogs of your breed are doing with their step count and Strain Score.
There are options to set yourself up as a mixed breed, so I'm in a category with Border Collies and Border Collie mixes, for example.
Sleep tracker for dogs: Using the Fi Collar to track your dog's sleep
An update to the Fi collar software in mid-2021, the Fi Series 2 also tracks your dog's sleep, if you feel it's safe to leave your smart dog collar on them overnight.
Like with people, getting enough sleep is important for dogs' health, both long-term, as well as short-term to help them recover from intensive workouts and the day's activities.
This is especially true for puppies and young dogs, especially dogs like me, who will move around all day if not given the opportunity to learn to relax and sleep.
The Fi sleep tracker shows how much time during a day your dog is sleeping, napping or awake, and shows this by the hour, day, week, and month. The left screenshot above shows what the app has tracked for my weekly sleep duration.
It also differentiates between sleep and naps (sleep is dark purple, and naps are a lighter shade).
It's not clear how it does this and whether it's mainly based on the time of day your dog is still (i.e. naps are during the day, sleep is at night), but I've found it to be reasonably accurate.
You can see a couple of days (Thursday and Saturday) where I had a lot of nap time, which isn't necessarily wrong, as my parents alternate my higher-activity days with calm days at home.
An example of the Fi's hourly sleep tracking is shown on the right of the image above. This is the Sunday from the weekly sleep tracking shown on the left.
This is a typical day, where I wake up between 6-7am, go for a walk, play, and bumble around for another hour or so, and then spend most of the day alternating between naps and moving around the house.
On that particular day, I went out in the early afternoon for a frisbee game and tricks and then hung out around the house until around 8.30 pm when I slept on the sofa with my parents until going into my crate for bedtime.
Using the Fi app
My parents like the Fi app and find it clean and easy to use. Some may say the app is overly-simplistic in terms of activity tracking as it mainly tracks your dog’s steps and GPS location points (as well as acting as a dog sleep tracker).
Simplicity, however, means they like the easy-to-use functionality, and hey, I’m a dog, not a pro athlete (yet).
With that in mind, I don’t think anyone in my family feels the need to get much more granular in terms of the details of my activity just yet, tracking steps and my sleep is enough.
In the future, though, perhaps a good direction for Fi to investigate would be heart rate tracking - imagine the possibilities!
We all know that for humans doing ‘X amount of exercise at a heart rate within a given range’ is better than just doing ‘X steps in a day’, so this would be an awesome feature.
Not sure how they’d get a good heart rate reading past all my hair, though…
Fi Series 2 vs Fi Series 3 Dog Collar Comparison
Here are the main differences between the two versions. While the Series 2 is no longer sold by Fi, you may be interested to know how similar or different they are, if you're familiar with the Series 2 and contemplating upgrading your dog's collar to the 3.
The most important difference is that Fi Series 3 is designed to connect with 40% more satellites and 200% LTE signal, which is great news because the critical tracking functions are only as good as the unit's ability to locate your dog using either GPS or LTE cell signal.
The Fi Series 3 collar is also 50% smaller than the Fi Series 2. The Fi Series 2 (as you can see in the photos in our image gallery at the end of this review) is still a compact unit, but this improvement makes it truly slimline and unobtrusive.
The newer version has greater pull resistance, which may be important to you if you have a strong dog that pulls and you intend to walk them with this collar.
It also has an even higher waterproof rating. I found Series 2's waterproofing to be perfectly great, but now you can pressure wash it if you want to (hopefully while it's not on your dog) and it should be fine.
Here's the full list of differences:
- 50% smaller - Fi Series 3 Module is half the size of the Fi Series 2 and lighter weight.
- 50% more pull force - Series 3 sports a full stainless steel body frame that can sustain 400 lbs of static force.
- Series 3 offers sizes Extra Small - Extra Large. See: What Size Fi Collar Should I Order?
- Collar choices - You can choose from 8 different collar choices for Series 3.
- 2x LTE network distance covered - All Fi Collar's LTE-M signal reaches about 30% farther than any conventional cellular network. With Series 3, Fi achieves another 100% in signal sensitivity to ensure your dogs can be located in the most remote areas.
- 40% more GPS satellites - Fi Series 3 uses the positioning satellite constellations GPS (US), Gallileo (Europe), GLONASS (Russia) and Beidou (China). That’s 78 satellites working to locate your dog within a 6ft radius.
- The Series 3 Collar is waterproof and rated both IP68 and IP66K.
How much does the Fi Dog Collar cost?
When you buy the Series 3 Fi collar, you can choose between a month-to-month, 6 months, one or two-year subscription, which ensures you have access to all the GPS and LTE coverage, and all tracking features the collar has to offer.
The month-to-month subscription costs $19, and the longer-term plans cost even less per month.
The 2-year subscription works out at $14/month, which is, in my opinion, an excellent deal, especially as there's no extra cost to buy the collar, so it's effectively free (or, well, the cost is baked into your subscription fee).
Use our exclusive coupon code TK20 via the link below to get $20 OFF your Fi Collar order - (Activation fee will be waived).
The Fi Series 3 Smart Dog Collar costs as little as $3.90 a week - that includes a dog collar and the small GPS device mounted on it, together with the base station that you plug in at home.
If you use our code 4C83FW via this link you'll receive an extra band free of charge which is nice if you like to mix up your look to keep your Instagram followers entertained. :)
My parents have had an ongoing subscription since getting the unit, so this Fi collar review is as in-depth as it could be, covering the GPS-specific features of the Fi Collar dog GPS tracker.
Do you need a Fi Subscription to use the Fi GPS Dog Collar as a dog tracker?
The subscription covers the GPS/LTE connection to the Fi collar - effectively, making it into a mobile device.
A subscription gives your parents access to the full capabilities of your dog's Fi collar - allowing for remote access to your location and activity.
If you buy the latest version of the Fi Collar, the Series 3, the price includes the full subscription and the collar itself, so you don't have the option NOT to have a subscription (this wasn't the case with the previous version).
Without a subscription, the Fi collar would still function - but if you go outside the range of your peoples' smartphone or your Fi Base, then nobody can use the Fi Collar's functionality to locate you.
This kind of defeats the point of one of the key functions of the Fi Dog Collar, that is, so that people can track you and have a much better chance of finding you if you wander off, so it seems that if you are considering getting your dog a Fi GPS collar, then you should get the subscription.
What cell / mobile phone network does the Fi Dog Collar use?
The Fi Dog Collar uses the AT&T network for locating your dog when he or she is out of the house alone, as well as Wi-Fi and Bluetooth-based safe zones.
Your own mobile phone does not have to be on the AT&T network for your Fi GPS Collar to work, the two are unrelated.
How do you attach the Series 3 GPS unit to the collar?
Let me guess... your parents bought you a new Fi collar (you lucky pup) but it's arrived and proving difficult to attach the unit to the Fi collar band itself... even using the included instructions?
Don't worry, we've got you covered (we had the same challenge). There's a sneaky extra step you need to take to be able to slide the GPS unit onto the collar attachment points. Watch this video to see how to do it:
You're welcome! If that helped, please do us a solid and like and comment on the video on our YouTube Channel!
How do you remove the Fi GPS Dog Collar's metal clips?
You may want to remove the metal clips from the Fi collar dog tracking device so that you can switch out the collars that you attach the Fi Smart Dog Collar to.
Quite a few dog collar brands are making 'Fi-compatible' Fi collar bands, which is pretty nice if you want a specific custom collar for your dog but also want to have the Fi device attached to it.
We've been asked this question a lot, and it's most easily explained in a video - see below for a demonstration of how to detach those clips from the Fi Series 2 collar.
My parents also attached the Series 2 Fi dog tracker unit to my favorite Ruffwear collar, which isn't a 'Fi-compatible' collar but they engineered it to work!
Have a read of this post if you're curious how to use the Fi collar dog GPS tracker with other brands of collar.
What Dog collar sizes are available and can you use the Fi Collar for cats?
No. The Fi smart dog collar is far too big for a pet cat to wear, unfortunately, and that goes for tiny dogs too.
This is a shame as a Fi collar for a cat would be great and I'm sure my feline brothers Coby & Champers would love to wear their own smart cat collar and look as cool and high-tech as me.
This leads me on to the Fi smart dog collar sizes that are available for purchase:
- Small - 11.5"–13.5" neck
- Medium - I wear a size medium Fi Smart Dog Collar, as my neck fits in the 13"–16.5" neck size range. In case I forgot to mention earlier, I'm a border collie and I weigh roughly 45 lbs.
- Large - 16"–22.5" neck
- Extra Large - 22"–34.5" neck
To see a more detailed sizing chart visit Fi's dog collar sizing chart and guide here.
Fi Collar Review: Is the Fi Dog Collar still the best GPS Dog collar?
Certainly on features, the Fi Dog Collar is one of the best dog tracking collars out there, and I have been using my Fi for 5 years now, and never had one break on me! By virtue of the long battery life, streamlined design and robust good looks, we’ve found it to be a great investment that I wear every day.
It gives my parents peace of mind that if I roam further than intended, they can quickly track me down and get me back safely.
I hope you enjoyed my Fi collar review and please let me know if you have any questions in the comments section below.
If you're looking for cool gifts to give the adventure-loving dog in your life, also check out our best dog gifts list for more ideas!
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