Apple now sells three Apple Watches, and for most sports the answer is the middle one. The Apple Watch Series 12 at $399 covers running, swimming and everyday health tracking on Apple’s own numbers, the Ultra 4 at $799 earns its price only if your day runs past 10 hours of workout tracking or your water goes deeper than 6 meters, and the SE 3 at $249 is the pick when notifications and activity rings are the whole job.
The gap that decides most of this is sensors, not straps. Apple’s SE 3 tech specs list no electrical heart sensor and no Blood Oxygen sensor, while the Series 12 and Ultra 4 share the new Health Sensing System that reads heart rate every five seconds and heart rate variability every five minutes.
Key facts: the three Apple Watches Apple sells
| Model | Price | Sizes | Water rating | Battery, normal and Low Power |
|---|---|---|---|---|
| Apple Watch SE 3 | From $249 | 40 mm, 44 mm | 50 m, swimproof | 18 hours, 32 hours |
| Apple Watch Series 12 | From $399 | 42 mm, 46 mm | 50 m plus IP6X, depth gauge to 6 m | 24 hours, 38 hours |
| Apple Watch Ultra 4 | From $799 | 49 mm | 100 m, EN13319 diving to 40 m, IP6X | 50 hours, 84 hours |
All three run watchOS 27 from Monday, September 14 and all three need an iPhone 11 or later running iOS 27. Series 12 and Ultra 4 are in stores on Friday, September 18.
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The activity table
| Activity | The published number that decides it | The pick |
|---|---|---|
| Running | Outdoor workout battery: 10 hours on Series 12 against 18, 25 and 45 hours on Ultra 4 | Series 12, unless a session runs past 10 hours |
| Swimming | 50 m water resistance under ISO 22810 on SE 3 and Series 12, with a depth gauge to 6 m and a water temperature sensor on Series 12 | Series 12 for pool and open water, Ultra 4 for diving |
| Hiking | 3000 nits, 84 hours in Low Power Mode, dual-frequency GPS and satellite on Ultra 4 | Ultra 4 |
| Desk work | 24-hour battery, ECG, Blood Oxygen and the new Readiness score | Series 12, or SE 3 at $249 if you skip the sensors |
Runners and hikers: what the Ultra 4 actually adds
For a runner the deciding figure is workout hours. Apple rates the Series 12 at up to 10 hours of outdoor workout tracking, which covers a marathon several times over. The Ultra 4 is rated at 18 hours, 25 in Extended Workout mode and 45 in a new Max Extended Workout mode that samples GPS every second and which Apple aims at 100-mile races. If your longest event fits inside 10 hours, the $400 gap buys battery you will not use.
Hiking is where the Ultra 4 case is strongest, and none of it is about running. It has 3000 nits of peak brightness against 2000 on the Series 12 and 1000 on the SE 3, precision dual-frequency GPS rather than precision L1, an on-wrist operating range of minus 20 to 55 degrees Celsius, and satellite Emergency SOS, Messages and Find My with two years included. Neither the Series 12 nor the SE 3 has satellite.
Swimmers: 50 meters covers more than people expect
The SE 3 and Series 12 are both rated to 50 meters under ISO 22810 and Apple calls both swimproof, so lane swimming and open water sit inside the specification for a $249 watch. The Series 12 adds a depth gauge rated to 6 meters, a water temperature sensor and an IP6X dust rating.
Diving is the dividing line. Only the Ultra 4 is rated to 100 meters and tested to EN13319 for recreational scuba to 40 meters, with depth accuracy of plus or minus 1 meter. Its Grade 5 titanium case weighs 63 grams and fits wrists from 130 to 210 mm, against 32.2 grams and 130 to 200 mm for the 42 mm aluminum Series 12.
Desk workers: what the $150 between SE 3 and Series 12 buys
The step from $249 to $399 is $150 by our arithmetic, and it is a sensor purchase. The Series 12 adds the electrical heart sensor for ECG, the Blood Oxygen sensor, heart rate every five seconds, HRV every five minutes, hypertension notifications, sleep score and the Readiness score. It also charges faster: 15 minutes gives 12 hours of normal use and five minutes gives 10 hours of sleep tracking, against 80 percent in about 45 minutes for the SE 3.
Audio Intelligence follows the same line. Apple says Sound Recognition alerts for sirens, alarms and doorbells require a Series 12 or Ultra 4, with Live Rewind and Siri Recap listed as beta features arriving late in 2026.
What has not been confirmed
- Apple publishes only starting prices for Watch. Titanium, ceramic, cellular and band prices are not on any page it serves.
- Apple has not published outdoor workout battery hours for the SE 3, so that row of the comparison cannot be filled.
- Apple names the Readiness app on the Series 12 and Ultra 4 pages and has not published a list of older watches that get it.
- Per-device AppleCare+ prices for Series 12 and Ultra 4 are not published. AppleCare One is $19.99 a month for up to three devices.
Series 12 and Ultra 4 pre-orders are open now, with both in stores on Friday, September 18. watchOS 27 arrives free on Monday, September 14 for the SE 3, Series 9 and later and Ultra 2 and later, the same day iOS 27 ships. Our event recap covers everything announced, and the SE 3 stock story from the week before explains why the entry model briefly vanished.
