Apple Watch Series 12 starts at $399, $150 more than the second-generation Apple Watch SE cost at launch in September 2022, and it replaces the SE’s S8 chip, 1000-nit display and 18-hour battery with an S11, 2000 nits and up to 24 hours, then adds ECG, Blood Oxygen and temperature sensing. The comparison matters this week because Apple’s watchOS 27 compatibility list leaves the SE 2 out.
Apple no longer sells the 2022 SE; the $249 slot belongs to Apple Watch SE 3. Everything below comes from Apple’s tech specs, compare page and press releases.
Key facts: Series 12 vs SE 2
| Item | Apple Watch Series 12 (2026) | Apple Watch SE (2nd gen, 2022) |
|---|---|---|
| Price | From $399, or $11.99 a month on Apple Upgrade | $249 at launch; no longer sold |
| Chip | S11, dual-core, 4-core Neural Engine, 64GB | S8 SiP, dual-core, 2-core Neural Engine, 32GB |
| Sizes | 42 mm and 46 mm | 40 mm and 44 mm |
| Peak brightness | 2000 nits, 1 nit minimum | Up to 1000 nits |
| Battery | Up to 24 hours, 38 hours Low Power Mode | Up to 18 hours |
| Heart sensors | ECG, Blood Oxygen, temperature, new optical sensor | Optical heart rate only |
| watchOS 27 | Ships with it | Not supported; stays on watchOS 26 |
Why the SE 2 is stuck on watchOS 26
Apple’s watchOS page states that watchOS 27 runs on Apple Watch SE 3, Series 9 through 12, and Ultra 2, 3 and 4. The second-generation SE is not on the list, nor are Series 7, Series 8 and the original Ultra. Its last major version is watchOS 26.
Don’t miss the best of The Mac Observer
Set us as a preferred source and our Apple reporting ranks higher in your Google Search results and Discover feed — one tap, no account changes.
So the SE 2 misses Siri AI on the wrist, the dynamic app grid, the Siri Modular face and the perimenopause features in Cycle Tracking that arrive with the free update on Monday, September 14. Our watchOS 27 release guide lists everything in the update.
Sensors: the biggest gap between the two watches
Apple’s SE 2 spec sheet lists no electrical heart sensor, no Blood Oxygen sensor, no temperature sensor and no depth gauge. Optical heart rate is the extent of its health hardware.
Series 12 carries a third-generation electrical heart sensor for ECG, a Blood Oxygen sensor, a temperature sensor, a depth gauge to 6 meters and a water temperature sensor. Its Health Sensing System measures heart rate every five seconds all day and HRV every five minutes, and feeds a daily Readiness score from 0 to 10.
- Hypertension notifications, sleep score and sleep apnea notifications, all listed by Apple for Series 12 and absent from the SE 2 spec sheet.
- A new Steps complication and what Apple calls the most accurate step tracking of any smartwatch.
- Audio Intelligence on the S11: Sound Recognition alerts, Live Rewind, Siri Recap and Shazam detection, processed in the chip’s Secure Exclave.
Display, chip, battery and charging
| Spec | Series 12 | SE 2 |
|---|---|---|
| Display | Always-On Retina, wide-angle OLED, LTPO3, 326 ppi, 2000 nits | Up to 1000 nits |
| Front crystal | Ceramic Shield 2 on aluminum (60 percent tougher than Ion-X); sapphire on titanium and ceramic | Apple has not restated |
| Materials | 100 percent recycled aluminum, 100 percent recycled titanium, ceramic | 100 percent recycled aluminum |
| Weight | 32.2 g (42 mm aluminum GPS), 39.5 g (46 mm aluminum GPS) | Apple has not restated |
| Water | 50 m, IP6X | 50 m |
| Charging | 80 percent in about 30 minutes; 15 minutes gives 12 hours | 80 percent in about 1.5 hours |
| Cellular | 5G RedCap and LTE | LTE |
Charging is the difference owners will feel daily. Apple rates the SE 2 at 80 percent in about 1.5 hours; Series 12 gets there in about 30 minutes, and a 15-minute top-up gives up to 12 hours. Battery rises from 18 to 24 hours, with a 38-hour Low Power Mode. Details are in our Series 12 battery and charging explainer.
The SE 2 came in aluminum only. Series 12 offers aluminum in four finishes, titanium in radiant gold and natural, and ceramic in pearl white and night blue, though Apple has published only the $399 starting price. Our Series 12 size and material guide walks through the options.
If $399 is too much: Apple Watch SE 3 at $249
Apple still sells a $249 watch, and it is on the watchOS 27 list. Apple Watch SE 3 uses the S10 chip with 64GB, a 1000-nit Always-On display in 40 mm and 44 mm, up to 18 hours of battery with a 32-hour Low Power Mode, and 80 percent charging in about 45 minutes. Apple lists a temperature sensor for it, but no ECG or Blood Oxygen sensor.
If ECG, Blood Oxygen, hypertension notifications and five-second heart rate tracking matter, only Series 12 delivers them. If you mainly want notifications, workouts and a supported watch, SE 3 keeps you on watchOS 27 for $150 less. Apple’s own framing of the two new watches is in our first Apple Watch buying guide.
What Apple has not said
- A trade-in value for the SE 2. Apple’s trade-in page asks condition questions before showing a figure and publishes no per-model estimate.
- Whether the SE 2 will keep receiving security updates on watchOS 26, and for how long.
- The SE 2’s weight, front crystal and Low Power Mode hours are not restated on Apple’s pages, so they are left blank above.
- Series 12 prices for titanium, ceramic and cellular models, and band prices.
Apple Watch Series 12 is available to pre-order now from $399, or $11.99 a month over 24 months on Apple Upgrade, and reaches stores on Friday, September 18. For the full announcement, read our Apple Watch Series 12 launch coverage.
