Amazfit T-Rex 3 Pro Review: Monster name, monster battery life

If you’re going to make a tough smartwatch, you may as well give it tough looks and a tough name, and they don’t get much tougher than the Amazfit T-Rex 3 Pro. When I was 12, I’d have been very excited to have an action-packed watch named after a dinosaur, and would have found just as much glee in its flashlight function too.

However, as an adult, will you want such a statement-making, and slightly silly smartwatch on your wrist? With the battery life this monster delivers? I’ll say yes, you probably will.

Specs, price, and availability

The Amazfit T-Rex 3 Pro costs $399 and in a first for the model line, it comes in two case sizes, 44mm and 48mm. You can see the 48mm version in our photos, in its standard Tactical Black color, plus it’s available in Black Gold too. If you go for the 44mm version, which has a slightly more subtle design, it also comes in Black Gold plus a Gold and Gray model too.

The smartwatch has a staggered release schedule with the Tactical Black 48mm version available on Amazon from September 5, with the Black Gold version following on September 25. The 44mm T-Rex 3 Pro will arrive before the end of the year, and will also be sold through Amazon.

It’s up against two obvious competitors, the Samsung Galaxy Watch Ultra and the Apple Watch Ultra 2, and does benefit from working with both Android and iOS through the Zepp companion app. There’s no subscription plan required to use and access the Zepp app’s data, but the Aura Wellness Advisor — which provides in-depth sleep reports and a sleep assessment, performance analysis, and relaxation tools — requires either a monthly subscription or annual payment.

Design that makes you say grrrrr

Tough as nails

There’s nothing subtle about the Amazfit T-Rex 3 Pro. The 48mm version is 14mm thick, and its slab sides means there’s no escape from it either. It troubles cuffs and often connects with walls as you pass by, and should you wear it to track sleep, it gets itself caught up in duvets and sheets too. With the strap, it weighs 76 grams, which is pleasingly lighter than the Samsung Galaxy Watch Ultra with its strap.

The case is made from a fiber-reinforced polymer, but the bezel and buttons are made from TC4 titanium alloy, with flat sapphire crystal over the 1.5-inch AMOLED screen, plus it’s water-resistant to 10ATM. There’s no military standard or IP rating credentials, but the strong, meaty construction makes it feel like it’ll withstand plenty of harsh treatment. The silicone strap has lots of stretch and a host of holes, so it’s easy to get the fit just right.

The titanium buttons are easy to locate and have a strong, precise motion. I like the metal guard at the 9 o’clock position, and appreciate the dual keepers to make sure the excess strap length is kept under control. The strap is attached using 22mm spring bars, which are a bit of a pain to operate without the help of a small screwdriver or similar prying tool. But it does mean you can swap to another strap if the silicone one isn’t for you.

It takes a few days to get used to the size and shape of the T-Rex 3 Pro, even if you’re experienced in the world of big watches. The T-Rex 3 Pro is an unashamed homage to the world of Casio G-Shock, and you need the same level of dedication to wear one all the time. It’s never uncomfortable, just noticeable.

I’ve worn it with my cuff tucked behind it, which has the knock-on effect of everyone else seeing it, and I’m not convinced it’s the most aesthetically pleasing watch. It’s purposeful though, and the always-on ambient screen gives the screen life when it’s not fully illuminated. The style isn’t going to be for everyone, but it’s well-designed and has the right toughness credentials to back up its name.

Battery monster

Charge and forget?

The 48mm T-Rex 3 Pro has a 700mAh battery inside, and even with heavy use, Amazfit expects it to last for 10 days on a single charge. You know what? It’s right. I’ve worn the T-Rex 3 for a week now, with the always-on screen active, continuous heart rate and blood oxygen monitoring, and a couple of workouts tracked, and the battery still has 55% remaining. I see no reason why it won’t reach 10 days before a recharge, and it’s excellent performance. The long battery life is really the number one reason to consider it over the other tough smartwatch alternatives.

A lot of the excellent battery life is due to strong efficiency. Sleep tracking takes just 1 or 2%, which is barely believable, and a 30-minute GPS walking workout doesn’t take much more from the battery either. Amazfit estimates the battery can last up to 25 days with low use too. Another factor in its efficiency will be the software, as it doesn’t run Google’s Wear OS, but Amazfit’s own Zepp OS 5.

You recharge the smartwatch using a proprietary plastic puck equipped with pogo pins, which magnetically attaches to the back of the T-Rex 3 Pro. You do need to make sure the connection is secure, as it can look as if it’s in place, but the smartwatch doesn’t charge. I haven’t needed to fully recharge it yet, but taking it from 50% to 100% took an hour, so you shouldn’t expect it to charge very quickly when it does require it. But if I’m only visiting the charger every 10 days, I wouldn’t care.

No Google software

But it doesn’t really matter

Is Zepp OS, and not having Wear OS, a downside? Not really, but it may depend on what you want. On-watch navigation and overall use is very similar to Wear OS, with swipes to show notifications, quick settings, and the app menu. Swipe up on the screen and you’ll see a command center, with small cards showing current health data points, and some shortcuts. It’s all very logical, and takes moments to learn.

By using its own operating system, Amazfit makes it possible to connect the T-Rex 3 Pro to both Android and iOS smartphones. I’ve been using it connected to the Google Pixel 10 Pro XL, and it has been totally reliable. Notifications have also arrived without a problem, and the haptic buzz on your wrist is suitably strong and noticeable.

The main thing to remember is the T-Rex 3 Pro doesn’t have access to the Google Play Store, or flashy Google AI features like access to Gemini on your wrist. You also miss out on rich, interactive notifications. Amazfit does provide its own AI assistant, and a selection of free and paid apps and watch faces through the Zepp app, however you won’t find the big names in there, and sometimes things get a bit convoluted.

Take Maps as an example. The T-Rex 3 Pro doesn’t use Google Maps or similar, and instead requires you to download a section of your required map in the Zepp app, then transfer it over to the smartwatch. It’s messy and time-consuming, and the instructions are vague at best, but at least the map is then available offline. If this sounds annoying, then you’re probably better off with a Galaxy Watch or a Pixel Watch. You aren’t missing out on many other features though, and the smartwatch has a speaker and microphone to take calls, Wi-Fi (but only 2.4GHz), and dual-band GPS.

Workouts and training

Made for adventure

Open the Workouts mode on the T-Rex 3 Pro, and you’ll find 180 different modes, all spread out over various menus, and including some very specific modes for those involved in HYROX fitness training, and both freediving and scuba diving.

The T-Rex 3 Pro does have auto workout tracking, but you have to set it up yourself by letting the smartwatch know which exercises it should look out for. The list of auto-tracked activities includes walking, running, swimming, and rowing. While you’re in this menu, you may want to turn off the voice guidance mode, as otherwise the smartwatch will shout your stats to everyone around you at set intervals. Handy if you’re biking, but really embarrassing if you’re just walking about.

Amazfit does not list the processor or how much RAM the T-Rex 3 Pro has, but performance is mostly acceptable, outside of waking the smartwatch up from its ambient screen. Crucially, there are no performance issues when navigating through the workout menus and getting started on an exercise.

By default, the watch screen locks when you start an activity, and it sensibly tells you how to unlock it when you go to interact with the screen. This probably doesn’t sound all that important, but it’s really helpful for newcomers. The physical buttons are also helpful when you’re exercising, as they all replace on-screen swipes, making it really easy to dismiss notifications or calls, or to check the different workout data screens it shows.

Regarding accuracy, the T-Rex 3 Pro matched my sleep and outdoor walk tracking data taken with the Oura Ring 4, and nothing stood out as being different to the data I’d expected to see. Neither are medical devices, so the exact figures may not be accurate.

Other fun features include a 200-lux flashlight. Yes, the smartwatch really does have a torch built in. Long-press the Up button, and it illuminates on the top of the smartwatch. Press the button again and it changes brightness, or turns to a red glow. There’s even a boost mode to make it even brighter, and it’s surprisingly effective.

Although you can’t download some of the most popular sporting apps, Zepp OS does link with Google Fit/Apple Health/Health Connect, Strava, Komoot, Adidas Running, Relive, and TrainingPeaks.

What’s different to the other T-Rex smartwatches?

Amazfit makes two other T-Rex smartwatch models, the T-Rex 3 and T-Rex Ultra. The main difference with the Pro model is its second case size, immediately separating it from the other models. The 44mm version has a toned down style, which you can see in the photo above, and it should help open the T-Rex line up to a few more buyers. This is also something no other “Ultra” smartwatch offers, where big case sizes are something wearers just have to accept.

Elsewhere, the T-Rex 3 Pro has several small differences to the other two models. For example, it doesn’t have the same stainless steel case as the standard T-Rex or Ultra model, and is the only one with the titanium alloy bezel. It has a larger screen and a bigger capacity battery than the Ultra, plus it’s lighter too, but is much closer in overall specification to the T-Rex 3. At this time, it may also be the only model with Zepp OS 5 and workout modes including freediving and scuba, but these may arrive as updates to the other smartwatches in the future.

Should you buy the Amazfit T-Rex 3 Pro?

The Amazfit T-Rex 3 Pro is a lot of fun. It doesn’t take itself as seriously as the Galaxy Watch Ultra or the Apple Watch Ultra 2, which I think is obvious by the choice of name. When I was 12, I know I’d have loved a watch named after a dinosaur, and now I’m, well, a lot older than that, I admit it’s still pretty cool. Silly, but cool.

Don’t let the absence of Wear OS put you off too much either. No, Zepp OS isn’t as deeply integrated with Android (so there’s no interaction with notifications, or app downloads either), but for the basics, along with comprehensive activity and health tracking, it works well. There’s informative sleep tracking, but due to the size of the 48mm smartwatch, not everyone will want to wear it overnight.

If you’re interested in a tough smartwatch, love a G-Shock, and want far longer battery life than the competition offers, the Amazfit T-Rex 3 Pro is a recommended buy.