Apple has released an Apple Watch almost every year since 2015, and the differences between generations are not always obvious from the model number. This chart compares every Series alongside the SE and Ultra lines, and explains which differences actually matter when choosing one.
Current as of August 2026. The lineup Apple sells new is the Series 11, Ultra 3 and SE 3 — all three share the same S10 chip. Everything else below is covered because it is still widely sold secondhand.
Apple Watch comparison chart
| Model | Year | Key additions over the previous model | Still supported? |
|---|---|---|---|
| Series 1 / 2 / 3 | 2016–2017 | Series 2 added GPS and 50m water resistance; Series 3 added optional cellular | No — no longer receive watchOS updates |
| Series 4 | 2018 | Much larger display (40/44mm), electrical ECG, fall detection | Ageing out |
| Series 5 | 2019 | Always-on display, built-in compass | Ageing out |
| Series 6 | 2020 | Blood oxygen sensor, brighter always-on display, faster charging | Yes |
| SE (1st gen) | 2020 | Series 4 body and sensors at a lower price — no ECG, SpO2 or always-on display | Yes |
| Series 7 | 2021 | Larger 41/45mm display with slimmer bezels, more durable glass, faster charging | Yes |
| Series 8 | 2022 | Temperature sensing (retrospective ovulation estimates), crash detection | Yes |
| SE (2nd gen) | 2022 | Faster chip and crash detection; still no always-on, ECG or SpO2 | Yes |
| Ultra | 2022 | 49mm titanium case, 100m water resistance, Action button, much longer battery, dual-frequency GPS | Yes |
| Series 9 | 2023 | S9 chip, Double Tap gesture, brighter 2000-nit display, on-device Siri | Yes |
| Ultra 2 | 2023 | S9 chip, 3000-nit display, Double Tap | Yes |
| Series 10 | 2024 | Thinnest Apple Watch yet, larger wide-angle OLED display, sleep apnea notifications, faster charging | Yes |
| SE 3 | 2025 | Gains the always-on display and the S10 chip — the SE line's biggest jump. 50m water resistance, fast charging | Current |
| Series 11 | 2025 | S10 chip, hypertension notifications, sleep score, tougher cover glass, 5G cellular | Current |
| Ultra 3 | 2025 | S10 chip, largest Apple Watch display, satellite communications and emergency SOS via satellite, 100m water resistance, 15-min fast charge to ~12 hours | Current |
Which differences actually matter?
Always-on display — the clearest dividing line
Introduced with Series 5, this keeps the watch face visible when your wrist is down. It is the single feature people notice most in daily use, and until 2025 it was the main reason to choose a Series over an SE. The SE 3 now has it, which substantially narrows the gap between the two lines.
Health sensors are the real generational split
Sensors accumulate rather than change: ECG from Series 4, blood oxygen from Series 6, temperature from Series 8, sleep apnea notifications from Series 10, and hypertension notifications from Series 11. If a specific health feature is why you are buying, check which generation introduced it — that determines your minimum model. Note that the SE line has never included ECG or blood oxygen at any generation.
One caveat worth knowing on the secondhand market: blood oxygen measurement was disabled on US-sold models for a period because of a patent dispute, and later restored through a software update. If you are buying used in the US, confirm the feature is active on that specific unit.
Size and display
Two jumps matter. Series 4 grew the case to 40/44mm, and Series 7 grew it again to 41/45mm with much slimmer bezels. Series 10 then made the watch noticeably thinner while enlarging the display again. Anything Series 3 or earlier will feel small and cramped by current standards.
Battery life
Every standard Apple Watch, from Series 1 to Series 11, is rated at roughly 18 hours — that has not meaningfully changed in a decade. What has improved is charging speed: Series 7 and later, plus every Ultra and the SE 3, support fast charging. The Ultra line is the only genuine exception on capacity, with multi-day battery life.
Cellular
Optional from Series 3 onward on standard models, standard on every Ultra. It only works if your carrier supports watch plans in your country, so check that before paying the premium.
Which Apple Watch should you buy?
- Most people: Series 11. The full sensor suite, always-on display and current software support.
- On a budget: SE 3. Now that it has the always-on display and the same S10 chip, it is closer to the Series 11 than any previous SE. You give up ECG, blood oxygen, temperature sensing and the hypertension and sleep apnea features.
- Endurance sports, diving, or off-grid: Ultra 3. Satellite communications, 100m water resistance and multi-day battery are things no other model offers.
- Buying used: Series 6 is the sensible floor — it has ECG and blood oxygen and still receives updates. Avoid Series 3 and earlier entirely; they no longer receive watchOS updates.
A note on charging away from home
The 18-hour battery rating is the practical constraint on every non-Ultra Apple Watch, and it is most keenly felt when travelling, because the Apple Watch needs its own proprietary charger — a normal USB cable or power bank will not work. Lexuma's XTAG MFi-certified Apple Watch portable charger is a keychain-sized battery that charges any Apple Watch series without carrying the puck and cable.
Specifications above are drawn from Apple's published comparison pages. Apple occasionally changes feature availability by region — check Apple's official comparison tool for the current position in your country.