We’ve been using the Fi Series 3 every day since it launched, and at this point? It is unquestionably our go-to GPS tracker for both of our coonhounds.
Fi focuses on tracking rather than boundary training. If you actually want a GPS fence, my SATELLAI vs Halo review compares two much closer matches.
I’ve long since been following Fi (you can see the series 2 review here), and using their products every day for the last two years on both of my coonhounds, and it passed the test for sure. So when the series 3 was released it was a quick decision that I needed to give this device a test.
So this post started with my early findings, but it now has something much more useful behind it: years of real, daily use on two high-drive hounds who are exactly the sort of dogs you buy a tracker for.
My Long-Term Verdict
2026 buying note: this is a long-term review of the Series 3 hardware we still use. Fi now sells newer trackers, including Series 3+, Mini and Ultra, so a new customer will normally be choosing from the current Fi range rather than buying this exact launch-era model. I have not quietly turned years of Series 3 experience into a review of hardware I have not tested.
Yes, I recommend the Fi Series 3—and not cautiously. We have used it every day since release, it is still our go-to tracker for Lucy and Shelby, and honestly? I can’t sing its praises highly enough.
Best for: escape-prone dogs, scent-driven breeds, multi-dog homes and guardians who want reliable location tracking with useful activity and sleep data.
Not the right tool if: you want a virtual boundary system. Fi is a tracker, not a GPS fence.
This is an affiliate link. Rebarkable may earn a commission if you buy through it, at no extra cost to you.
Whilst this product was supplied for free by fi, it has not coloured my review, or swayed my opinion in any way. It’s also good to note that the links in here are affiliate links so I will get a small percentage – but it doesn’t cost you anything.
What Is A GPS Collar & Why Would You Need One?
A GPS Collar is a “Global Positioning System” tracker on the collar of a dog. Why you might need one varies enormously. Some people use the fi collar for an activity tracker, a route tracker and to keep a general eye on your dog’s health (because changes in sleep and activity can indicate medical issues), but mostly, users like myself use it as a back up. Because they’ve got dogs who, if they get out, or break a leash will be gone.
For us, we use trackers because our coonhounds have a substantial prey drive and consequently the last time they got out properly, they were gone for six days and Mr Rebarkable was lucky to get them back (this was before I was ‘around’ properly). The trackers give both of us peace of mind that the hounds are where they’re meant to be, or decrease the time between out and found.
Long-Term Testing Update
I originally began testing the Fi Series 3 collar in December 2022. We have used it every day since on both of our coonhounds, so this is no longer a first-look review—it’s based on years of living with the device, the app and the alerts in an actual multi-dog home.
Introducing: Fi Series 3
- 400lbs load tested collar
- Sleep Tracking
- Activity tracking
- Smallest device (28g)
- Locates within 6ft
- Geofencing (aka a digital alert when dog leaves safezone)
- IP68 & IP66K
- Great community features
The fi series 3 is the new generation for the Fi GPS tracker, and overall, it's a much sleeker design that resolves the old issue of the weak attachment links. It's app and GPS functionality are fantastic, though I've yet to see any dramatic benefit from the extra satellites - but I'll keep this as updated as I can through my journey.
What Changed From Fi Series 2 To Series 3?
If you’ve already got a series 2 collar then you might be looking at the series 3 and wondering if you should upgrade. So, I want to just go through the changes that exist between them so. you can make an informed decision. But if you’re not looking to upgrade…
The device size
The Series 3 is a minuscule 28g vs the fi series 2’s 40g, so they’ve shaved off over 25% of the weight and not compromised a single feature, which means that this device is no longer just for big dogs, instead its for pretty much all dogs
The Way You Buy
At launch, Series 3 changed Fi’s buying model by bundling the hardware and service into a subscription-style plan. That historical detail explains the original review, but it is not a current price quote: Fi’s plans, hardware options and introductory offers change, so check the live terms before buying.
The Collar links
Fi have changed the collar links between the devices. They work similarly, but the actual way they connect to the device is no longer up and around, it’s more in line. To me, I see that this is what gives the collar the added strength.
The problem with this is that if you bought a collar for your s2 device, because of the change in links it will not work with your s3 device. Yep. This is a huge disappointment.
Whilst I understand that this is absolutely done with purpose and it’s a great purpose, it’s still a kicker for anyone who invested in the makers collars that can cost as much as $120.
What’s In The Box
Set up is pretty easy with the s3; even transferring over my dog’s profiles from the series 2 to the series 3 was relatively simple.
What I Love About The Fi Series 3
It’s So Small
When Series 3 launched, its much smaller tracker was one of its strongest improvements over Series 2. It sits neatly on the collar and has worked well for our hounds, but it should not be compared with today’s market as though no newer trackers have appeared since 2022.
Load tested collar
Previously, the fi series 2 came with a collar that was rather well known for it’s literal weak links. And, even though the collar was designed to give added security, the weak links connecting the collar to the device meant that the collar could snap if the dog it was on tended to pull on the leash or react.
Luckily this time around it’s been tested!
Note: It’s worth noting that only large and extra large sizings come with a metal buckle, smaller collars come with a plastic buckle.
The App
The app is still fantastic. It’s the same app as the S2, so it still has some of the multi-dog clunkiness, but overall? It’s really nicely done. I still love the Sleep tracking (because overtiredness is real and it’s a problem!), the newer strain score is interesting but I’m not sure how truly valuable it is? And I still love the rankings and how it gives you the option to compare your dogs to other dogs, and even see how their activity changes month by month
What I Don’t Love About The Fi Series 3
Transferring…
Oh my gosh, the transfer was way tougher than I thought. There was no “click here” or “scan this” or directions on what to do?
I did figure it out, and essentially you go into the app, deactivate the existing collar, and then it pops up if you want to activate the new collar.
Launch-Era Glitches
At launch, some owners reported glitches with escape alerts and walk tracking. Our own transfer lost a few days of data, but that early criticism needs the context of years of use: the Series 3 has since been reliable enough to become our everyday tracker on both hounds.
Support Was Stretched At Launch
Support appeared stretched when Series 3 launched, much as it had around Series 2. I am keeping that in the review because it was part of the launch experience, but I would not present it as a measurement of Fi’s current response times without retesting support today.
It’s black stainless steel…
I mean – it looks wonderful – it’s a very attractive design. However, whether your dog is scratching, or they’re running around, rolling in things, or just being a dog, the black stainless steel scratches really quick. It’s a shame too, because it is a really attractive design, and it looks so slick, in against the old device and on the collar? Ugh, divine.
Do You Recommend the Fi Series 3
Yes. After years of daily use, I don’t just quite like the Fi Series 3—I trust it. Lucy and Shelby wear theirs every day, and it remains our go-to tracker for both hounds.
Is it perfect? No piece of pet tech is. But it has earned its place in our routine through actual reliability, and that’s rather more meaningful to me than a shiny feature list.
If our long-term Series 3 experience makes Fi sound right for your dog, see Fi’s current tracker range and live pricing. Choose the current model that fits your dog’s size, coverage needs and charging routine rather than assuming this exact 2022 hardware is still the default buy.
Author, Ali Smith
Ali Smith is a professional, qualified, and multi-award winning trainer is the founder of rebarkable. She has always believed animals deserve kindness and champions force free methods. Believing that dog guardians will all choose the kindest options if proper information is provided, she aims to help all dog guardians who need it and make dog training as accessible as possible
Ali lives win Maryland, US with her husband and her three dogs.
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