Between the Fenix 8 (47mm) and Vantage V3, the Fenix 8 (47mm) comes out ahead in battery life and water resistance, while the Vantage V3 wins on weight. Overall, the Fenix 8 (47mm) scores 64.3 and the Vantage V3 scores 53.5 on our Mars Score.
Which should you buy?
The Fenix 8 (47mm) is the clear pick on raw spec strength, leading by 10.8 points on the Mars Score. The margin is wide enough that the underdog only makes sense if its individual strengths line up with what you specifically need.
Pick the Fenix 8 (47mm) if your top frustration with your current device is running out of charge before the day ends — endurance is the lead spec here. The biggest gaps in its favor are battery life, water resistance, display size.
Pick the Vantage V3 if you carry the device everywhere and weight or thickness has been the deciding factor before. Its strongest claims are weight.
Both ship with comparable ecg, cellular, spo2, so those specs don't separate the two — focus on the differences below.
Bottom line: the Fenix 8 (47mm) is the safer default. The other model is the right choice only when its specific advantages line up with your priorities.
Why Garmin - Fenix 8 (47mm) wins
- ▲Battery life — 128.57% more. 384 h vs 168 h.
- ▲Water resistance — 5.00 ATM more. 10 vs 5.
- ▲Display size — 0.72% more. 1.4 " vs 1.39 ".
Why Polar - Vantage V3 wins
- ▲Weight — 16.00 g less. 57 vs 73.
Spec comparison
Design
| Spec | Garmin - Fenix 8 (47mm) | Polar - Vantage V3 |
|---|---|---|
| Case size | 47 mm | 47 mm |
| Weight | 73 g | 57 glead |
| Case material | fiber-reinforced polymer | aluminum |
| Water resistanceⓘ | 10 ATMlead | 5 ATM |
Display
| Spec | Garmin - Fenix 8 (47mm) | Polar - Vantage V3 |
|---|---|---|
| Display size | 1.4 "lead | 1.39 " |
| Always-on display | true | true |
| Peak brightnessⓘ | 1000 nits | 1000 nits |
Health & Fitness
| Spec | Garmin - Fenix 8 (47mm) | Polar - Vantage V3 |
|---|---|---|
| ECG | true | true |
| SpO2 | true | true |
| Temperature sensor | true | true |
| Sleep tracking | true | true |
| Blood pressure | false | false |
Battery & Connectivity
| Spec | Garmin - Fenix 8 (47mm) | Polar - Vantage V3 |
|---|---|---|
| Battery life | 384 hlead | 168 h |
| GPS | true | true |
| Cellular | false | false |
| NFC | truelead | false |
| OS | Garmin OS | Polar OSlead |
Frequently asked
Which has longer battery life, Fenix 8 (47mm) or Vantage V3?+
Fenix 8 (47mm) lasts 384h vs 168h.
Do Fenix 8 (47mm) or Vantage V3 support ECG?+
Both support ECG.
Which has cellular, Fenix 8 (47mm) or Vantage V3?+
Neither offers cellular.
Spec-level deep dives
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