Fi collars are probably the best-known pet tech on the market. The tracker is connected to an app on your phone, which lets you check your dog’s location even from far away. The tracker was designed for active dogs, so it’s sturdy, and the tracker unit is water- and dirtproof so you have nothing to worry about on your adventures.

We have reviewed the original Fi collar four years ago so I was interested in comparing Fi Series 3 Smart Collar to our experience with the previous one.

How does it work?

The Fi Tracker uses satellites, Bluetooth, and the cell network to monitor your dog’s location. This was the first tracker to communicate the location to the app through AT&T’s LTE-M cellular network, which makes it possible to have (so far) unbeatable battery life. All Fi Collar’s LTE-M signal reaches about 30% farther than the conventional cellular network and the Series 3 collar offers another 100% in signal sensitivity to ensure your dogs can be located in remote areas.

Sidenote that this has nothing to do with your phone’s network. Your phone doesn’t have to be on the AT&T network to communicate with the tracker.

The tracker complies with FCC’s regulations on radio frequency (RF) electromagnetic fields for humans and does not have significant emissions - only 1/100th of a cell phone’s energy - so it’s safe for both you and your dog.

To save you some time right at the beginning: if you are reading this from outside of the US (and some parts of Canada), the Fi tracker will not work for you! You can only download the Fi app from US app stores. You can use this map to check the coverage in your area.


Fi Series 3 Smart Collar

Sleek & smart

Third generations of Fi's location tracking collar with unbeatable battery life

Disclaimer: this review contains affiliate links, which support Dog Gear Review if you purchase the product after clicking on it without costing you anything extra. Using affiliate links will never compromise us in writing unbiased, honest reviews!

What Is the Difference Between Fi Series 2 and Series 3?

  • Fi3 is 50% smaller and lighter than the Fi2 collar to fit more dogs
  • 50% more pull force: full stainless steel body frame that can sustain 500 lbs of static force.
  • 2x LTE network distance covered
  • 40% more GPS satellites - Fi Series 3 uses the 78 positioning satellite to locate your dog within a 6ft radius.
  • Series 3 Memberships include Fi’s Extended Hardware Warranty.

Battery life

Using the LTE-M network pushes out the battery life significantly and Fi can go up to 3 months with one charge in certain situations, while it drains in two days if the dog is away from home and the owner and the Lost Dog Mode is running.

The Fi collar also comes with a “Home Base” that you keep plugged in at home and connect to your wifi. When the collar is within reach of the Base, it is in “Wifi Mode” and saves battery by communicating to the Base. When the dog is around you, the collar is connected to the Fi app and communicates the location via Bluetooth for the same reason.

On this page, you can find details on the battery life

The new charging solution and base is very cool: it is a small magnetic unit that looks a lot more hi-tech than the original charger. You can snap the collar on top without plugging in anything and it charges fairly quickly.

 Fi 3 Smart Collar and Activity Tracker Review | Dog Gear Review

Lost Dog Mode

If your dog gets loose, you can start “Lost Dog Mode” by clicking on the “Track Lost Dog” icon on the map in your app. On the Series 2 collar, this mode gives you location updates every minute and turns on the red light on the collar to make it more visible, while the Series 3 gives you live updates.

Creating safe zones is another useful feature if you are worried about your dog running away. You can set multiple zones in the app (under the dog’s profile) and get a notification when the app recognizes that your dog has left the perimeters of your home, dog park, or your parent’s yard. Setting larger areas ensures that these notifications will be more accurate but they still might be sent with minutes delay.

LED Light

The collar has a built-in LED light that even has different color options! You can turn the light on and off from the app’s main page, even if your dog is far away from you.

The setting for the different colors for the collar is not intuitive: you have to open the side menu, go to “Collars,” tap on the collar, and set the color from there. You can pick between red, green, blue, purple, yellow, cyan, and white!

The light is visible from farther away but it tends to face the ground due to the weight of the unit, therefore you don’t really see it from the distance unless it’s pitch-dark and it lights up the dog’s environment. The light is slowly blinking - more like brightening up and fading periodically, which looks very neat. If you look for a very bright, highly visible light, this is not it, but it’s a great idea to have a built-in feature for it in case it gets dark on your walk and you don’t have anything else on you.

The Fi Collar Band

The tracker comes with four collar colors and Fi3 has two additional sizes: XS and XL to fit more dogs. The collar band is wide and sturdy looking, but it did get really dirty and worn-looking quickly.

The other problem with the Fi collar is that it is made of a shiny “seatbelt-like” material which makes it loosen up all the time to its full length. I need to re-adjust it at the beginning of every walk and it fully loosens up by the end of the walk even though Zulu barely pulls on the leash. She could easily slip this collar by the end of the walk which is not a concern with her but I know it is for others.

Luckily Fi works with third-party collar makers to create unique and custom collar designs for their trackers. Most of the time, you have to order the tracker from Fi and contact the vendors separately regarding your collar, but some of them also sell the tracker now, so check out your options before placing your order!

The list of approved Fi Makers is available on the Fi website.

 Fi 3 Smart Collar and Activity Tracker Review | Dog Gear Review

The App

The app that you download to your phone is very easy to use. The UI is user-friendly and mostly intuitive. On the main tab, you have the history with all the activities and other notifications. You can also turn on the LED light from here with the icon in the right-top corner.

The “Community” and the “Rank” pages are the social aspects of this app where you can find other Fi users around you or see how your dog compares to other dogs. All your achievements are easily shareable on social media.

There is also a Timeline tab where you can see the latest activities and previous notifications.

Fi Series 3 Collar Review

I really enjoyed using the Fi Series 3 collar over the last months and it gave me peace of mind especially while traveling with or without Zulu. All trackers have their limitations, but the coverage and reaction time of the Fi system were pretty good compared to other trackers we have used in the past and are significantly improved compared to their first version.

I loved the look of the sleek new tracker module and the magnetic feature of the charger/base unit.

I was happy to see that the Fi 3 can more or less accurately recognize driving times and not confuse them with walks which was my pain point with some trackers and I believe it wasn’t implemented in the first Fi collar version we used.

 Fi 3 Smart Collar and Activity Tracker Review | Dog Gear Review

With regular daily walks, 1-2 hikes a week, and a training day away from home, I usually got 4-5 weeks battery life. After traveling for a SAR seminar for 4 days (and not having the base with us), we still had 45% battery life when we got home which was better than I expected.

While Fi is very strong in the lost dog scenario, and battery life - activity tracking is not one of its strengths. When showing walks on the map, they use an algorithm to make the route more accurate which results in the track “sticking to” roads/trails even if you walked across a field so the distance estimations can be pretty inaccurate.

The algorithm adjusting the track is pretty neat as long as it finds the actual trail you took. In the suburbs, it put our tracks on different streets or showed us walking around buildings while we were just standing in the park, so it clearly has its limitations. Most of the time, it did adjust the track pretty well and it’s a lot nicer than just putting down a location point every few minutes and connecting them with a straight line.

 Fi 3 Smart Collar and Activity Tracker Review | Dog Gear Review

The collar doesn’t track the dog’s actual steps, it just estimates it from the distance walked (location points along the route) and other data which means that on the same walk, a dog walking next to you on a leash would get the same steps as the dog running around you in a circle.

It still provides you nice charts on the dog’s activity and sleep data that you can review for trends but don’t rely on them too much:


Daily view of the steps taken in the Fi app


Weekly sleep/nap data (Zu usually doesn't wear the collar inside)

While Fi fixed many issues related to the physical collar compared to the first version, this is still the weakest point of the Fi3. The collar band continuously loosens up as the dog runs around or pulls on the leash making it easy for them to slip it if they want to.

Another issue I have run into is that the module started discoloring Zulu’s fur after the first two months. I don’t know if it’s the connector piece or the unit itself but there is a very visible black section on her white fur and the hair is also breaking under the unit. This is not a huge concern health-wise but if you have a dog with white fur around the neck, it is very visible and hard to get rid of even with shampooing.

The issues with the collar band are weird to me because the sleek tracker module is so well-made and the tech is really good. I would think the easiest part of this product would be to find a simple collar band that is durable and performs well. There are plenty of Fi makers offering collars where the collar band goes all around and the unit is placed on top of it, so it is not in contact with the dog’s fur which is always an option. However, it would be good to have a solid collar that comes with the tracker.

The biggest con of Fi is that it needs a cellular network to communicate but this is the limitation of all similar trackers. This means that the tracker will not work AT ALL if you do not have cell coverage or run out of mobile data. Not only that the tracking will not work, but you cannot even open the app at all without data and cell coverage.

Like every other tracker that uses cellular, Fi also requires a subscription plan (and a one-time activation fee) to work outside your wifi range. They have a few different options from month-to-month pricing to prepaying for up to 2 years so you can find a solution that works for you.

 Fi 3 Smart Collar and Activity Tracker Review | Dog Gear Review

Functionality review

We keep pointing out that no product will work perfectly for every need and in every situation. With trackers, it all depends on your primary use case for the product.

Let’s see if the Fi collar knows what you want from a tracker!

Is Fi Series 3 Collar a good option if I’m worried about my dog getting loose and running away?

The best thing about this collar is that it tracks your dog continuously, and you can see their real-time location at any time. You can just open up the app to see where they are and while in “Lost Dog Mode”, it will give you live location data. Just as with other GPS products, the accuracy will be around 6 feet on an open field (more in a forest or between hills) but that should be enough to locate them. As discussed above, you can also set up safe zones to get notifications when your dog leaves the current zone.

While these are great features, you shouldn’t have unrealistic expectations. Keep in mind that the tracker will not work all the time correctly, so if your dog is regularly running away from your yard, you still want to keep an eye on them. GPS and LTE signals are inconsistent, and coverage can be interrupted by many environmental factors. Depending on the collar mode, you get a location every 5 minutes (live tracking only in Lost mode), which can mean that in the worst-case scenario, your dog left the safe zone a while ago by the time you get a notification. If you have wifi or coverage issues, or an older phone that isn’t working well in general, you will probably also experience issues with the Fi app.

So, in short, it’s beneficial for emergencies - like when the dog bolts through the door or gets loose from the leash and runs away on a walk. It works very well when you actively look for your dog with the app open. You will find it less useful if you want to leave your dog in your yard without supervision and watch a movie, hoping that the app will keep an eye on the dog for you and you get an immediate notification.

 Fi 3 Smart Collar and Activity Tracker Review | Dog Gear Review

Is the Fi Series 3 Collar a good option for tracking how much my dog is running around while we are hiking?

Since you only get a location every 5 minutes, the dog’s track and activity details are highly inaccurate and are based on general estimations. It’s also not useful if you hike in the backcountry where you have spotty or no cell coverage.

I don’t know how their algorithm calculates the steps exactly, but if e.g. we played fetch on the same spot for 10 minutes, that will not count as miles walked, and most times it doesn’t show more steps than when we just walk around in the same area without Zu running.

Fi 3 is a great location tracker but their activity tracking is not strong which is probably done to preserve battery time.

Is Fi Series 3 Collar a good option to track my dog’s overall activity level?

As discussed above, the collar calculates steps with an algorithm. The “Miles walked” is not the sum of the steps, it’s based on approximate location data. These stats are still a good way to track your dog’s general activity and trends in their exercise - even when you are not home. You can set a step goal for the dog and achieve “streaks” when you reach the goals multiple days in a row.

There is also a social aspect of the app where you can check how your dog’s activity compares to other dogs’ stats based on location or breed to keep you motivated. There is also a “Fi Community” tab where other owners share photos of their dogs so that you can bond with other owners.

Is Fi Series 3 Collar a good option to check on my dog while they are with a dog sitter or at the doggie daycare?

The Fi collar sends you notifications when the dog leaves the house or gets home and you can check on their activities when they are out or look back at the Timeline tab to see their activities for reference.

We have to mention one more time not solely to rely on these notifications. Since the connectivity can be inconsistent and inaccurate. The collar often sends a push notification saying “The dog is without an owner,” even when I am standing right next to them or more frequently when we are home and the collar is next to the base.

Fi is excellent to give you peace of mind when someone else is walking your dog and to be sure they can find them if something happens. You can add your dog walker/family members to the app with different permission levels so they can use the app and toggle the “Lost Dog Mode” when needed. Keep in mind that depending on the permission level, the person might also have access to all your walks and see where you are with the dog later.

Fi Series 3 Review Summary

Altogether this is a very well-made collar with smart features!

It is important to understand how the Fi collar works and what one can expect from this collar. Many frustrated reviews are coming from users who do not understand the limitations of a cell-based tracker in general and have unrealistic expectations when they buy it.   We feel this collar is mostly targeted towards people who are afraid their dog would run away and not come when called. The impressive battery life is definitely their selling point and we haven’t had issues with that so far.   The Fi collar can also be the perfect choice if you have to trust someone else with your dog. It gives you peace of mind that the person can track the dog’s location if your usually obedient pup decides to ignore the other person and start chasing squirrels in the forest.   It can be used to track hiking/walking stats and general activity levels, but these are not the areas in which Fi excels.

We can’t push enough that connectivity to wifi/Bluetooth and the cellular network itself can be spotty or interrupted by the environment and can cause problems outside of Fi’s responsibility. It also relies on your phone providing accurate GPS location - which is better for some phones and worse for others. When reading disappointing reviews from others, it’s hard to distinguish if it is an actual failure of the product or something to do with the environment or network.   Fi is a good backup and can be a lifesaver in emergencies, but any electronics can and will have blind spots. Knowing their location or getting a notification that they left the safe zone will not keep them from being run over by a car before you get there.

To summarize, this is a cool gadget that gives you peace of mind, especially when someone else is taking care of your dog or if you have a new dog who is still working on recall. It’s always good to know that you can get their more or less accurate location if something unexpected happens but it’s just as important to know the limitations of the system and manage expectations accordingly.


Fi Series 3 Smart Collar

Sleek & smart

Third generations of Fi's location tracking collar with unbeatable battery life

Disclaimer: this review contains affiliate links, which support Dog Gear Review if you purchase the product after clicking on it without costing you anything extra. Using affiliate links will never compromise us in writing unbiased, honest reviews!

Suggested Reviews


Invoxia’s Smart Dog Collar, acclaimed with seven international awards, including the CES Innovation Award from 2022, stands out as an advanced canine technology. This innovative device is not only alocatiopn tracker but it also integrates cutting-edge sensors and artificial intelligence algorithms to revolutionize canine preventive healthcare with the goal of enhancing the well-being of our dogs.


About Link Link is a tracker module that you can attach to any collar or harness to track your dog’s location and activity. It’s worth mentioning that the company also had two previous products called Link AKC and Link Plus, which came integrated into a collar, so keep an eye on which product you are reading a review on because all these tend to be called “Link tracker” in different articles.


What is the TEK 2.0 GPS Tracking System? The SportDOG TEK 2.0 is a professional GPS Tracking System designed with hunting and working dogs in mind. It has fantastic features and many hunting-specific features: like being able to track up to 21 dogs at once or having data on the sun and moon rising/setting.


What is a beeper? Beeper collars use a motion sensor to determine what the dog is doing and “beep” based on the user’s settings so the owner knows from far away what their dog is up to.


What is the PitPat Activity Monitor? The Pitpat tracker is the dog version of the smart wristbands that more and more people wear every day. It is a small, lightweight module that only logs in the activity - meaning this is NOT a location tracker.


About Tractive Tractive is an Austria-based company specialized in pet wearables. They used to offer different activity trackers and separate GPS trackers for dogs and large animals (like horses), but today they only sell the product called “Tractive GPS.


What is Findster? Findster is a GPS tracker unit that you can attach to any collar. The best part is that there is no subscription needed, you only pay for the device, and there are no other recurring fees!


What is a Whistle Collar? Whistle currently has three pet trackers, the Whistle Fit - a fitness tracker without GPS, the Whistle Go, and its upgraded version with new features and longer battery life: Whistle Go Explore.


What is a Fi Collar? Fi is probably the best-known pet tech right now on the market. The tracker is connected to an app on your phone, which lets you know your dog’s location even from far away.


Cross Winds Leather, founded by Elena in Pennsylvania (USA), specializes in creating durable and aesthetically pleasing pet gear by combining top-grain leather and climbing rope. Their mission is to offer high-quality, long-lasting products while maintaining transparency, accountability, and responsibility in their business practices.