Amazfit T-Rex 3 vs Garmin Forerunner 170: which should you buy?

Answer worked out Oct. 31, 2026

Amazfit T-Rex 3 price: Checked Oct. 30, 2026

Garmin Forerunner 170 price: Checked Oct. 30, 2026

Most people: get the Amazfit T-Rex 3, because it costs at least 15% less today.

On an iPhone: the Amazfit T-Rex 3 works better with your phone.

Get the Amazfit T-Rex 3 for outdoors and hiking.

Get the Garmin Forerunner 170 if you want heart rate and sleep.

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Amazfit T-Rex 3 vs Garmin Forerunner 170

Amazfit T-Rex 3
AMAZFIT

Amazfit T-Rex 3

$244.99 at Best Buy
Garmin Forerunner 170
GARMIN

Garmin Forerunner 170

$299.99 at Garmin
  1. Amazfit T-Rex 3: 10 ATMWater resistance−5 ATMGarmin Forerunner 170: 5 ATM
  2. Amazfit T-Rex 3: 68.3gWeightDifferent testsGarmin Forerunner 170: 41 g
  3. Amazfit T-Rex 3: 1.5 in AMOLED, 480 × 480, up to 2,000 nits, Gorilla GlassDisplayGarmin Forerunner 170: 1.2-inch AMOLED touchscreen, 390 x 390 pixels, optional always-on mode
  4. Amazfit T-Rex 3: Typical use: up to 27 days; accurate GPS: up to 42 hrs; GPS max: up to 180 hrsBatteryGarmin Forerunner 170: Smartwatch mode: up to 10 days, or 4 days with the display always on
  5. Amazfit T-Rex 3: $244.99Price today$55 apartGarmin Forerunner 170: $299.99
Amazfit T-Rex 3
Buy at Best Buy$244.99
We may earn a commission.
Garmin Forerunner 170
Buy at Garmin$299.99
We may earn a commission.
All the details

Key differences

  • Water resistance: 10 ATM vs 5 ATMAmazfit T-Rex 3: 10 ATM (10 ATM; certified for freediving to 147 ft (45 m)) ConfirmedSourceGarmin Forerunner 170: 5 ATM ConfirmedSource
  • Weight: 68.3g (without strap) vs 41 g (condition not stated), measured differentlyAmazfit T-Rex 3: 68.3g (68.3g without strap) ConfirmedSourceGarmin Forerunner 170: 41 g ConfirmedSource

From each maker's own specifications. A point is listed only when both makers state a figure and the two differ; a point either maker does not state is left out, never guessed. Two figures measured under different conditions are shown side by side, not compared.

Who should buy which

  • The Amazfit T-Rex 3 Guide names it for outdoor adventure, hiking and navigation.Outdoor adventure: Military-grade build, freediving certification to 147 feet, and it shrugged off rocky Colorado mountain terrain. Source linkedSourceHiking: It logs up to 42 hours in accurate GPS mode during extended hiking trips. Source linkedSourceNavigation: Dual-band GPS across six satellite systems keeps your position accurate outdoors, and one GPS charge lasted nearly 40 hours. Source linkedSource
  • The Garmin Forerunner 170 Guide names it for running, fitness and sleep.Running: Garmin Coach plans adapt to your recovery each day, and GPS felt spot on for runs up to 10K. Source linkedSourceFitness: More than 80 sports apps cover swim, bike and strength days, with training readiness and training status telling you how hard to go. Source linkedSourceSleep: Each night brings a sleep score, a sleep coach and HRV status to show how well you recovered, on a watch that weighs 41 grams. Source linkedSource

From what each Guide names the product best for.

Side by side

FeatureAmazfit T-Rex 3Garmin Forerunner 170
Display1.5 in AMOLED, 480 × 480, up to 2,000 nits, Gorilla Glass1.2-inch AMOLED touchscreen, 390 x 390 pixels, optional always-on mode
BatteryTypical use: up to 27 daysSmartwatch mode: up to 10 days, or 4 days with the display always onAmazfit27 daysGarmin10 days
Weight68.3g without strap41 gAmazfit68.3 gGarmin41 g
Water resistance10 ATM5 ATMAmazfit10 ATMGarmin5 ATM
ConnectivityDual-band GPS, 6 satellite systemsBluetooth and ANT
Design48.5 × 48.5 × 13.75mm42.6 x 42.6 x 11.9 mm case, five buttons plus a touchscreen
Works withiPhone and Android , Zepp appiPhone and Android, Garmin Connect app

Garmin Forerunner 170

Buy at Garmin$299.99
Checked Oct. 30, 2026

We may earn a commission.

Works with your phone

iPhone
WorksWorks with limits
Android
WorksWorks

Sources

AmazfitGarmin NewsroomGarmin
Amazfit T-Rex 3 vs Garmin Instinct 3