Sport, GPS, autonomy, water: what really matters outside

On the pure sport side, the two watches share the same philosophy: multi-band GNSS, stable tracking, very numerous sports profiles (170+ on T-Rex 3, a little more on Pro), downloadable offline maps. For hiking, trail running, mountain biking, running, you are clearly in the right category.

On a marked course of around 18 km with around 600 m of D+, the T-Rex 3 and 3 Pro both remained less than 1% apart from a reference watch dedicated to trail running. The tracks remain clean, even in somewhat dense undergrowth. Does the Pro do “better” to the point of justifying a change of model? No. It's great to use.

If you ride a lot in the forest or in the mountains, and you want to compare the T-Rex to other MTB-oriented watches, take two minutes to read our detailed advice for choosing a reliable MTB GPS watch, it gives you a broader perspective.

Autonomy in real scenario

The raw figures are close, but we are going to talk concrete, not brochure. On a typical scenario of 12 days with notifications activated, 4 sports sessions (3 GPS outings of approximately 1 hour 15 minutes, a weight training session), and auto screen:

• T-Rex 3: from 100% to approximately 38%.
• T-Rex 3 Pro: from 100% to around 34% (flashlight and brightness required a little more).

You get the idea: both can easily last a week, often two, without recharging. Autonomy should not be your main criterion when choosing between the two. That would be a bad idea.

Water, rain, apnea: how far you can go

Both watches advertise resistance to 10 ATM, with certification for diving/freediving up to 45 m. For swimming, snorkeling, recreational freediving, “normal” water trips, you are very wide. You can keep them on your wrist without thinking as soon as there's water in the equation.

The T-Rex 3 Pro pushes the “experiential” imagination a little further with an assumed positioning on extreme cold and recreational diving, but in fact, both remain robust multisport watches, not technical diving computers. Don't ask it to replace a real computer if you do deep diving with complex decompression.

For pure hiking – elevation, changeable weather, long days outside – the T-Rex are well positioned in the landscape that we detail in our selection of hiking watches that really change everything.