Readers like you help support XDA Developers. When you make a purchase using links on our site, we may earn an affiliate commission. Read More.

Quick Links

There are general smartwatches that can perform a variety of tasks and keep you connected to your smartphone. Then, there are purpose-driven watches that are designed to excel in specific areas. The new Amazfit T-Rex Ultra is one of the latter.

The T-Rex line has always been about being rugged in terms of looks and intent. But the Ultra model, as you'd expect by the name, pushes these features to the limit by using more durable build materials in the case. It has passed 15 military-grade durability tests with the ability to withstand temperature ranges from 158 degrees Fahrenheit (70 degrees Celsius) to -40 degrees Fahrenheit (-40 degrees Celsius). It has 10ATM water resistance equal to 100 meters, so Amazfit included a feature for free diving up to 30 meters. Heck, even the battery life is extreme, with up to 20 days of typical use.

As with Amazfit's other watches, like the GTR Mini we recently reviewed or the GTR 4, the T-Rex Ultra is a health and fitness companion for less adventurous exercises as well. Being able to have a watch that you know can track all of your health metrics and withstand nearly anything you throw at it is worth a lot. But all of these features do come at a cost. This isn't a cheap watch, and for some people, the design is going to be too much. However, if you like, or can accept, the style and weight of the Amazfit T-Rex Ultra, it won't let you down.

About this review: This review was written after three weeks of testing an Abyss Black T-Rex Ultra provided by Amazfit. The company did not have input in this review.

Amazfit T-Rex Ultra in Sahara color
Amazfit T-Rex Ultra
9 / 10

The Amazfit T-Rex Ultra is the ultimate smartwatch for rugged adventures. Thanks to the fantastic battery life, bright and vivid display, extreme durability, and intelligent health tracking, this smartwatch can handle anything you throw at it.

Brand
Amazfit
Battery Life
Average usage up to 20 days
Operating System
Zepp OS 2.0
Onboard GPS
Dual-band & 6 satellite positioning systems
Customizable Strap
yes, 22mm
Case Material
Stainless steel: bezel, back panel, bridge and buttons. Polymer alloy middle frame
Colors
Abyss Black and Sahara
Display
1.39-inch, touchscreen AMOLED, 454x454 (326PPI)
Battery
500mAh
Connectivity
Wi-Fi 2.4GHz and Bluetooth 5.0 BLE
Durability
810G passed 15 U.S. military-standard tests, Low Temperature Mode Certification, Freediving Certification
Health sensors
BioTracker PPG biometric sensor for heart rate, blood oxygen saturation, and stress monitoring
Dimensions
47.3x47.3x13.45mm
Weight
89g
Workout detection
25 strength training movements and 8 sports movements
Exercise modes
160+ including Track Run mode, Smart trajectory correction, Virtual pacer
Pros
  • Excellent build quality
  • Superior battery life
  • Insanely durable
  • Wide-range of health and fitness features
Cons
  • Heavy and bulky for some people
  • Limited notification interaction
  • Missing key third-party app support

Amazfit T-Rex Ultra: Pricing and availability

Amazfit T-Rex Ultra on wrist in direct sun

Amazfit announced the T-Rex Ultra on March 20, 2023. The watch comes in two colors — Abyss Black and Sahara — for $400 through Amazon and Amazfit.

Design and build: A beast in every way

Amazfit T-Rex Ultra from the side sitting on barbed wire

There's no denying that the T-Rex Ultra looks tough. That has been the case for all the devices that have come before it in the series, like the T-Rex 2. But to help this watch earn the Ultra tag, Amazfit had to upgrade to 316L stainless steel to replace the reinforced plastics. This switch brings additional durability, although it makes it quite heavy at 89g.

Looking at this smartwatch beside the T-Rex 2 or T-Rex Pro, you can see the design lineage hasn't strayed too far. You still get the exposed screws and four knurled physical buttons on the watch's sides. There's the metal guard with Amazfit emblazoned on it that protects the barometric sensor. However, Amazfit has changed how the watchband connects to the case. Now the 22mm silicone strap is much easier to replace. On previous T-Rex watches, the bands could technically be replaced, but they either needed a special screwdriver or an adapter in order to complete the swap. The Ultra uses a T4 torx screw, and though it isn't overly common, it also isn't anything proprietary.

Amazfit T-Rex Ultra with a T4 screw drive and a third-party band installed on the watch

The other part I like about the watchband connection point is the articulating lugs. While many other watches, both smart and otherwise, have extending lugs where the band connects, the connection point on the Amazfit T-Rex Ultra moves. So instead of a potential gap between the watch strap connection point and your wrist, the lugs can flex up and down to close any gaps. Not only is the watch more comfortable and secure on your wrist, but it also helps to keep debris from getting between your wrist and the watch.

The Amazfit T-Rex Ultra is a fantastic option for anyone that wants a super durable watch with amazing battery life and a vast suite of health features.

However, the accents and openings along the top of the strap collect debris easily. Considering the watch is designed to go on muddy and dirty adventures, the strap is going to bring a lot of the terrain back with it. That being said, the band itself is flexible and relatively comfortable; I just don't care for the style.

All of this rugged exterior is designed to help keep the environmentally-sensitive insides safe. The 10ATM water resistance rating is suitable for up to 100 meters of water pressure. I have worn this watch through a rainstorm while unclogging a gutter, working on my tractor, and burning pastures — it doesn't show a scratch. While the display isn't made of sapphire like the Amazfit Falcon, it's still quite durable.

Packed inside the T-Rex Ultra is a 500mAh battery that's rated from 10 hours in low-temperature mode with GPS to 50 days in clock mode. During my testing, I enabled all the health monitoring features, always-on display, sleep tracking, and notifications, and I got 5–7 days of battery, depending on what activities I was doing during the week. Recharging the watch with the magnetic USB-A cable takes about two hours from zero percent. The rating for a typical usage scenario is 20 days, according to Amazfit, so your battery life will vary depending on how you use it.

Amazfit T-Rex Ultra back showing the BioTracker senso and charging contacts

Speaking of health tracking, the T-Rex Ultra uses Amazfit's BioTracker PPG biometric sensor to monitor your heart rate, blood oxygen saturation, and stress levels. Compared to other smartwatches, like the Samsung Galaxy Watch 5 Pro and Google Pixel Watch, the T-Rex Ultra produced very similar readings.

Amazfit has been making strides over the past couple of years in the GPS department so that's also accurate here. For the T-Rex Ultra, Amazfit went with a dual-band and six-satellite positioning system to greatly improve not only the accuracy but also the speed at which the watch can obtain your location. When going on an outdoor run, the T-Rex Ultra latched onto my location much faster than the Galaxy Watch 5 Pro I wore at the same time. It also did a better job of accurately tracking the distance. I ran a very familiar path, so I know where different distances are, and the T-Rex Ultra was spot on at each increment, whereas the Galaxy Watch 5 Pro was off by about a couple hundredth of a mile at the first half mile. While that isn't much, that adds up over three miles.

Software: Nearly everything you could want

Amazfit T-Rex Ultra on wrist taking a heart rate reading

The T-Rex Ultra runs Zepp OS 2.0, and if you've read my review of the Amazfit GTR Mini, much of this section will sound very familiar. For those who haven't, the operating system is custom for Amazfit and can work with the best iPhones or Android smartphones using the Zepp app. ​On the watch itself, you can use the 1.39-inch AMOLED touchscreen to navigate the interface or the four physical buttons on the sides of the watch.

Zepp OS 2.0 is fast and offers a lot of ways to customize and view your stats. Swiping from the left brings you to the notifications screen. From here, you can respond to messages with preset replies — no keyboard or microphone here. Do note that the notifications don't clear out automatically when you dismiss them on your phone. To clear them away, you have to scroll to the bottom of the screen and tap on delete.

A swipe from the bottom of the homescreen brings up the Shortcut Cards, which are like widgets where you can quickly glance to get information on the weather, your last workout, sleep tracking, alarms, and more. What cards are shown can be customized from the Zepp app on your phone. Tapping on a card will take you to that app, so you can dig deeper into those metrics.

Amazfit T-Rex Ultra showing workout metrics

Swiping down from the top brings out the quick toggles for things like the flashlight, find your phone, brightness, do not disturb, and others. You get your apps when you swipe right. Now, I've written about my feelings about smartwatches and apps, so I don't want what I'm about to say to seem like it's a dealbreaker, but the app selection is limited. You won't find many third-party apps like Google Maps, WhatsApp, or others.

That said, the Zepp app store has grown over the last couple of years and is starting to offer some great options. There's a GoPro app so you can control your action camera from your wrist; Navigation Wear for turn-by-turn navigation prompts on the watch; and there are plenty of utility apps like calculators, menstrual cycle trackers, water intake trackers, and others.

You won't find many third-party apps like Google Maps, WhatsApp, or others. That said, the Zepp app store has grown over the last couple of years and is starting to offer some great options.

The other part of the software equation is the Zepp companion app for your phone. This app can do a lot, so much so that it can be overwhelming. But once you get the hang of it, it's great. You can manage nearly every facet of the watch while connected to it, from display settings to what apps are available, viewing health metrics, and more.

One of my absolute favorite parts of the Zepp app is its ability to switch between watches and/or phones without requiring a factory reset of the watch. While this may be a bit niche for someone like myself that uses multiple phones, if you needed to reset your phone for some reason or get a new one, you'll appreciate this feature too. The ease with which I can simply log into the app and tap the watch I want it to connect to without any resets or downloads is fantastic.

After you've gotten your T-Rex Ultra set up the way you want, the thing you'll use the Zepp app for most will be to review the various health and fitness metrics recorded from the watch. While you can view most of the same info from your wrist, the app does provide more info in some instances, and it's easier to view on your phone's larger display. Speaking of fitness, the T-Rex Ultra can track over 160 different workouts, including smart recognition of 25 strength training movements and eight different sports. There are also some more advanced tracking options for running, like smart trajectory correction and a virtual pacer.

Should you buy the Amazfit T-Rex Ultra?

Amazfit T-Rex Ultra beside the T-Rex Pro, T-Rex 2, and Amazfit Falcon
From left to right: Amazfit T-Rex Ultra, T-Rex Pro, T-Rex 2, and Amazfit Falcon.
From left to right: Amazfit T-Rex Ultra, T-Rex Pro, T-Rex 2, and Amazfit Falcon.
 

You should buy the Amazfit T-Rex Ultra if:

  • You like the Casio G-Shock watch style
  • You need a watch that is nearly indestructible
  • You don't want to have to charge your watch frequently
  • You need a watch with highly accurate GPS and an excellent health and fitness suite

You shouldn't buy the Amazfit T-Rex Ultra if:

  • You want a small and lightweight watch
  • You are on a tight budget
  • You need specific third-party apps

I have used a lot of smartwatches from a variety of brands, and the T-Rex line has become one of my favorites. I don't mind a heavy, rugged-style watch. The durability features are essential because of the types of activities I do, and I don't want to have to worry about my watch getting damaged. Zepp OS continues to improve in meaningful ways, even though third-party app support is lacking. But it makes up for it by being very responsive, providing loads of features, and being very efficient, which leads to excellent battery life.

The T-Rex Ultra is the pinnacle of all the series stands for. It's unapologetically rugged in design, and it backs that up with its capabilities. In the health and fitness category, the watch is going up with some stiff competition not only from the likes of Samsung and Apple but also Garmin, Polar, and others. At $400, the T-Rex Ultra is not a cheap watch. But considering all it brings to the table, it's worth it. The Amazfit T-Rex Ultra is a fantastic option for anyone that wants a super durable watch with amazing battery life and a vast suite of health features.

Amazfit T-Rex Ultra in Sahara color
Amazfit T-Rex Ultra

The Amazfit T-Rex Ultra is the ultimate smartwatch for rugged adventures. Thanks to the fantastic battery life, bright and vivid display, extreme durability, and intelligent health tracking, this smartwatch can handle anything you throw at it.