Samsung Galaxy Watch8 vs Samsung Galaxy Watch Ultra (2025)
The real choice is the kind of watch: the Galaxy Watch8 is a smartwatch and the Galaxy Watch Ultra (2025) is a sports watch. Beyond that, the Galaxy Watch8 is lighter, while the Galaxy Watch Ultra (2025) lasts longer (80 hours) and is rated 10 ATM.
We earn a commission from qualifying Amazon purchases made through our links, at no extra cost to you. This never affects our specs. How we make money.
Key differences
-
Battery life
Galaxy Watch Ultra (2025) wins
The Samsung Galaxy Watch Ultra (2025) lasts up to 80 hours against 40 hours.
-
GPS
Evenly matched
Both have built-in GPS with similar features.
-
Display
Evenly matched
Both have AMOLED screens of a similar size.
-
Health
Evenly matched
Much the same health sensors.
-
Weight
Galaxy Watch8 wins
The Samsung Galaxy Watch8 is lighter: 34 g against 60.5 g.
Other differences
- Type Depends on you
They're built for different jobs: the Galaxy Watch8 is a smartwatch and the Galaxy Watch Ultra (2025) is a sports watch.
- Water rating Galaxy Watch Ultra (2025) wins
The Galaxy Watch Ultra (2025) is rated 10 ATM against 5 ATM, better for snorkelling and water sports.
Which one should you choose?
Choose the Galaxy Watch8 if…
- You want apps, messages and a bright screen first: it is a full smartwatch.
- You wear it to bed or have small wrists: it weighs 34 g.
- You want it to slide under a sleeve: it's 8.6 mm thick.
Choose the Galaxy Watch Ultra (2025) if…
- Training comes first: it is a sports watch built around GPS, battery and workout data.
- You hate charging: it's rated for up to 80 hours in smartwatch mode.
- You snorkel, surf or swim in open water: it's rated 10 ATM.
Full spec comparison
The Galaxy Watch8 leads on size and durability, while the Galaxy Watch Ultra (2025) leads on battery life.
Green cells with a ✓ mark the better spec in that row. Tick "Show differences only" to hide the rows where they match.
Overview
| Spec | Samsung Galaxy Watch8 | Samsung Galaxy Watch Ultra (2025) |
|---|---|---|
| Brand | Samsung | Samsung |
| Series | Galaxy Watch | Galaxy Watch |
| Released | 2025-07 | — |
| Replaces | — | Galaxy Watch Ultra |
| Versions | 40 mm, 44 mm | Titanium Blue, Titanium Silver, Titanium Grey, Titanium White |
| Colours | Graphite, Silver | Titanium Blue, Titanium Silver, Titanium Grey, Titanium White |
| Also sold as | Galaxy Watch 8, Watch8 | Galaxy Watch Ultra LTE (47mm) |
Platform & apps
They are different kinds of watch, so start with how you will use it.
| Spec | Samsung Galaxy Watch8 | Samsung Galaxy Watch Ultra (2025) |
|---|---|---|
| Operating system | Wear OS | Wear OS |
| Works with | Android only | Android only |
| Minimum Android | Android 12 | Android 11 |
| Chipset | Exynos W1000 | Exynos W1000 |
| RAM | 2,000 MB | 2,048 MB |
| Storage | 32 GB | 64 GB |
| App store | — | Yes |
Display
The screens are closely matched.
| Spec | Samsung Galaxy Watch8 | Samsung Galaxy Watch Ultra (2025) |
|---|---|---|
| Display type | AMOLED | AMOLED |
| Display name | Super AMOLED | Super AMOLED |
| Screen size | 1.5 in | 1.5 in |
| Resolution | 480 x 480 | 480 x 480 |
| Pixel density | 327 ppi | — |
| Peak brightness | 3,000 nits | 3,000 nits |
| Colour display | Yes | Yes |
| Always-on display | Yes | Yes |
| Touchscreen | Yes | Yes |
Design & durability
Each watch has its strengths on size and durability.
The Galaxy Watch8 is lighter, is slimmer and comes in 2 sizes, while the Galaxy Watch Ultra (2025) is rated 10 ATM.
| Spec | Samsung Galaxy Watch8 | Samsung Galaxy Watch Ultra (2025) |
|---|---|---|
| Case sizes | 40 / 44 mm | 47 mm |
| Case shape | Round | Round |
| Dimensions | 46 x 43.7 x 8.6 mm | 47.4 x 47.1 x 12.1 mm |
| Thickness | 8.6 mm | 12.1 mm |
| Weight (case) | 34 g | 60.5 g |
| Case material | Armor Aluminium | Titanium grade 4 (partial) with plastic and Grade 2 titanium |
| Lens | Sapphire crystal | Sapphire crystal |
| Back material | Sapphire glass | — |
| Band fitting | — | Dynamic Lug System |
| Water resistance | 5 ATM | 10 ATM |
| IP rating | IP68 | IP68 |
| Water standard | — | ISO 22810:2010 |
| MIL-STD-810 tested | Yes | Yes |
| Operating temperature | — | -20 to 55 °C |
| Max altitude | — | 9,000 m |
Battery
The Galaxy Watch Ultra (2025) is ahead on battery life.
It lasts longer (80 hours), and the Galaxy Watch8 doesn't beat it on anything here.
| Spec | Samsung Galaxy Watch8 | Samsung Galaxy Watch Ultra (2025) |
|---|---|---|
| Battery (smartwatch mode) | 40 hours | 3.3 days |
| Battery (GPS) | — | 2 days |
| All battery modes | Smartwatch: 40 hours; Always-on display: 30 hours | Smartwatch: 3.3 days; Always-on display: 2.5 days; Battery saver: 4.2 days; GPS: 2 days |
| Battery capacity | 435 mAh | 590 mAh |
| Battery type | Built-in battery | Built-in battery |
| Charging | wireless | wireless |
| Wireless charging | Yes | Yes |
| Full charge time | 78 min | 98 min |
GPS & navigation
Both have built-in GPS with similar capabilities.
| Spec | Samsung Galaxy Watch8 | Samsung Galaxy Watch Ultra (2025) |
|---|---|---|
| GPS | Built-in | Built-in |
| Multi-band GPS | Yes | Yes |
| Satellite systems | GPS, GLONASS, Galileo, BeiDou | GPS, GLONASS, BeiDou, Galileo |
| Navigation features | — | turn-by-turn, back-to-start |
Health & sensors
Both track much the same health data.
Heart rate, sleep and the extra sensors line up closely.
| Spec | Samsung Galaxy Watch8 | Samsung Galaxy Watch Ultra (2025) |
|---|---|---|
| Sensors | optical HR, ECG electrode, SpO2, skin temperature, accelerometer, gyroscope, barometer, compass, ambient light, EDA | optical HR, ECG electrode, EDA, accelerometer, gyroscope, barometer, compass, ambient light, thermometer |
| Heart-rate sensor | — | BioActive Sensor |
| Heart-rate tracking | 24/7 | 24/7 |
| ECG | Yes | Yes |
| Irregular rhythm alerts | Yes | Yes |
| High/low heart-rate alerts | — | Yes |
| Blood oxygen (SpO2) | Yes | Yes |
| Skin temperature | Yes | Yes |
| Blood pressure | cuff-calibrated | cuff-calibrated |
| Sleep tracking | Sleep coaching | Sleep coaching |
| Sleep apnea alerts | Yes | Yes |
| Stress tracking | Yes | Yes |
| Energy score | Energy Score | Energy Score |
| Cycle tracking | Yes | Yes |
| Body composition | Yes | Yes |
Safety
Both offer much the same safety features.
| Spec | Samsung Galaxy Watch8 | Samsung Galaxy Watch Ultra (2025) |
|---|---|---|
| Emergency SOS | Via phone | From the watch (LTE) |
| Fall detection | Yes | Yes |
| Siren | — | Yes |
Training
Training features are evenly matched.
| Spec | Samsung Galaxy Watch8 | Samsung Galaxy Watch Ultra (2025) |
|---|---|---|
| Auto activity detection | Yes | — |
| Triathlon / multisport | — | Yes |
| Swim tracking | — | Pool |
| Training metrics | VO2 max, Personalised Functional Threshold Power | VO2 max, training load, recovery time |
| Adaptive coaching | Yes | Yes |
| Running dynamics | Yes | — |
| External sensors | — | power meter |
Smart features
The Galaxy Watch Ultra (2025) is ahead on smart features.
It has more storage (64 GB), and the Galaxy Watch8 doesn't beat it on anything here.
| Spec | Samsung Galaxy Watch8 | Samsung Galaxy Watch Ultra (2025) |
|---|---|---|
| Notifications | Yes | Yes |
| Message replies | Android | Android |
| Calls on the watch | Yes | Yes |
| Speaker | Yes | Yes |
| Microphone | Yes | Yes |
| Voice assistant | Gemini | Gemini |
| Contactless payments | Yes | Yes |
| Payment service | Google Pay | Samsung Wallet |
| Cellular | LTE version available | LTE version available |
| eSIM | — | Yes |
| Music storage | Yes | Yes |
| Wi-Fi | 802.11a/b/g/n 2.4GHz+5GHz | 802.11a/b/g/n 2.4GHz+5GHz |
| Bluetooth | Bluetooth 5.3 | Bluetooth 5.3 |
Diving, golf & more
Neither has a specialist edge here.
| Spec | Samsung Galaxy Watch8 | Samsung Galaxy Watch Ultra (2025) |
|---|---|---|
| Specialist modes | — | ski |
| Diving | — | None |