Between the Watch SE 3 and Watch Ultra 2, the Watch SE 3 comes out ahead in weight, while the Watch Ultra 2 wins on peak brightness / battery life. Overall, the Watch SE 3 scores 56.1 and the Watch Ultra 2 scores 60.5 on our Mars Score.
Which should you buy?
The Watch Ultra 2 edges ahead on the Mars Score (56.1 vs 60.5), but the 4.4-point gap is small enough that the right pick comes down to which spec advantages matter to you.
Pick the Watch SE 3 if you carry the device everywhere and weight or thickness has been the deciding factor before. The biggest gaps in its favor are weight.
Pick the Watch Ultra 2 if your top frustration with your current device is running out of charge before the day ends — endurance is the lead spec here. Its strongest claims are peak brightness, battery life, display size, among others.
Both ship with comparable cellular, so those specs do not separate the two — focus on the differences below.
Bottom line: there is no wrong answer here — match the spec advantages to how you actually use the product. The Mars Score parity says both are well-rounded; the differences are about trade-offs, not quality.
Why Apple - Watch SE 3 wins
- ▲Weight — 28.40 g less. 33 vs 61.4.
Why Apple - Watch Ultra 2 wins
- ▲Peak brightness — 200.00% more. 3000 nits vs 1000 nits.
- ▲Battery life — 100.00% more. 36 h vs 18 h.
- ▲Display size — 7.87% more. 1.92 " vs 1.78 ".
- ▲Water resistance — 5.00 ATM more. 10 vs 5.
- ▲Has ECG.
- ▲Has SpO2.
Spec comparison
Design
| Spec | Apple - Watch SE 3 | Apple - Watch Ultra 2 |
|---|---|---|
| Case size | 44 mm | 49 mmlead |
| Weight | 33 glead | 61.4 g |
| Case material | aluminum | titanium |
| Water resistanceⓘ | 5 ATM | 10 ATMlead |
Display
| Spec | Apple - Watch SE 3 | Apple - Watch Ultra 2 |
|---|---|---|
| Display size | 1.78 " | 1.92 "lead |
| Always-on display | false | truelead |
| Peak brightnessⓘ | 1000 nits | 3000 nitslead |
Health & Fitness
| Spec | Apple - Watch SE 3 | Apple - Watch Ultra 2 |
|---|---|---|
| ECG | false | truelead |
| SpO2 | false | truelead |
| Temperature sensor | false | truelead |
| Sleep tracking | true | true |
| Blood pressure | false | false |
Battery & Connectivity
| Spec | Apple - Watch SE 3 | Apple - Watch Ultra 2 |
|---|---|---|
| Battery life | 18 h | 36 hlead |
| GPS | true | true |
| Cellular | true | true |
| NFC | true | true |
| OS | watchOS | watchOS |
Frequently asked
Which has longer battery life, Watch SE 3 or Watch Ultra 2?+
Watch Ultra 2 lasts 36 hours vs 18 hours.
Do Watch SE 3 or Watch Ultra 2 support ECG?+
Watch Ultra 2 supports ECG; Watch SE 3 does not.
Which has cellular, Watch SE 3 or Watch Ultra 2?+
Both offer cellular variants.
Spec-level deep dives
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