Garmin Fenix 8 vs Oura Ring 4: Is the Garmin Fenix 8 Worth £550 More?
Garmin Fenix 8 or Oura Ring 4? We compare price, measured performance and real-world trade-offs to work out which is the better buy.
Maya Okonkwo
The short answer
Garmin Fenix 8 at 10ATM, dive to 40m against Oura Ring 4 at 6g. Where they part company is who they suit: the Garmin Fenix 8 is the one to get if you are endurance athletes and anyone off-grid for days, the Oura Ring 4 if you are people who care about sleep specifically rather than workouts.
Price difference: The Oura Ring 4 undercuts the Garmin Fenix 8 by £550. That gap only matters if the extras below are ones you will actually use.
Specifications side by side
| Specification | Garmin Fenix 8 | Oura Ring 4 |
|---|---|---|
| Price | £899 | £349 |
| Our score | 5 / 5 | 4 / 5 |
| Display | 47mm AMOLED | — |
| Battery | 16 days mixed use | 7 days |
| GNSS | Multi-band GPS, GLONASS, Galileo | — |
| Sensors | HR, SpO2, barometer, depth | PPG, temperature, SpO2 |
| Rating | 10ATM, dive to 40m | WR100 |
| Material | — | Titanium |
| Weight | — | 6g |
How we tested
Every figure quoted above comes from the same protocol, run on every unit in this category. This one spent three weeks worn continuously, including overnight. Worn on the non-dominant wrist alongside a chest-strap heart rate monitor and a second reference watch, with all figures logged from the same sessions.
| What we measure | How |
|---|---|
| Heart rate accuracy | Beat-by-beat comparison against the chest strap across steady runs, intervals and weights. |
| GPS accuracy | The same 5km loop, twelve times, compared against a surveyed route. |
| Battery life | A fixed daily pattern — one hour of GPS exercise, always-on display, sleep tracking — run to empty. |
| Sleep tracking | Compared against a manual log of actual sleep and wake times over fourteen nights. |
| Durability | Worn through cooking, washing up and the gym, with no attempt to protect it. |
We deliberately do not report step counts, which every device on the market gets close enough that the differences are noise.
The honest caveat: Wrist-based heart rate is least accurate exactly where people care most — high-intensity intervals.
Where the Garmin Fenix 8 wins
- Sixteen days of measured battery life
- The best GPS accuracy we have recorded
- Genuinely rugged construction
It also has the edge on the intangibles: it traced a wooded valley route within four metres of a surveyed track.
Where the Oura Ring 4 wins
- The most accurate sleep staging we have tested
- Completely unobtrusive at six grams
- A week of battery life
And in day-to-day use, it matched a clinical test within tolerance across five nights.
The trade-offs
Neither is flawless. The Garmin Fenix 8 has one clear weak point — very expensive — and the Oura Ring 4 has its own: a mandatory subscription. Weigh those against how you actually work rather than against the spec sheet.
The value case
The Garmin Fenix 8 costs £550 more and scores 1 point higher — roughly £550 per point of difference. Whether that is good value depends on whether the extra buys you sixteen days of measured battery life, or only a number. In our testing it is the former, but only just.
If neither quite fits
Look at the Galaxy Watch 7 at £289 — it scored 4 out of 5 and suits Galaxy phone owners who want deep integration. If the budget will not stretch, the Fitbit Charge 6 at £139 is the cheapest option in this category we would still put our name to.
Living with each of them
On paper the gap looks like a specification difference; in use it is a habits difference. With the Garmin Fenix 8 the thing you adjust to is very expensive, and you do adjust — within a week it stops registering. Its display (47mm AMOLED) is the part you stop thinking about. The Oura Ring 4 asks for a different accommodation: a mandatory subscription, against a material of Titanium that holds up better than the number suggests. Neither compromise is severe. They are simply different, and which one you would rather not think about is a more useful question than which is objectively smaller.
Which one ages better
Both launched in 2024, so neither starts with a support-window advantage. The other half of ageing is the weak point you already know about: very expensive on one side, a mandatory subscription on the other. Weaknesses of that kind do not improve with firmware, so assume you are buying them for the life of the device and price the decision accordingly.
Our recommendation
For most people we would take the Garmin Fenix 8, which scored 5 out of 5 in our testing against 4 for the other. That said, a score is a summary, not a substitute for knowing what you need.
Buy the Garmin Fenix 8 for sixteen days of measured battery life. Buy the Oura Ring 4 for the most accurate sleep staging we have tested.
Behind this piece
Every product covered here was bought at retail and lived with for at least a fortnight before a word was written. Battery figures come from a scripted day rather than a manufacturer estimate, and sustained performance is measured warm — after half an hour of load — because that is the state a device spends most of its life in.
Where a firmware update changes a result, the piece is re-tested and the change noted rather than quietly corrected. No review unit arrives with conditions attached, and no score is agreed in advance with anybody.
Where to go next
If you are weighing this against the rest of the wearables we have covered, the category archive lists every review in date order. The closest comparisons we have published are Garmin Fenix 8 vs Pixel Watch 3: Is the Garmin Fenix 8 Worth £550 More? and Garmin Fenix 8: Battery Draining Faster Than It Should.
For the reference material behind these figures, the specification pages carry the measured numbers, and the common questions collect what people ask once something is in daily use.
