Apple Watch Series 10 vs Apple Watch Ultra 4

Apple unveiled Series 10 on 9 September 2024 and put it in stores on 20 September; Ultra 4 followed on 9 September 2026. Series 11 and Series 12 came in between, and Series 12, also from $399, now has the same Health Sensing System as Ultra 4. So this is a two-year-old everyday watch against the newest Ultra, and Series 10 is still supported: it gets watchOS 27 like every Series 9 or later.

Side by side

Spec	Apple Watch Series 10	Apple Watch Ultra 4
Announced	9 September 2024	9 September 2026
Sizes	42mm or 46mm	49mm only
Thickness	9.7mm	12mm
Case	Aluminum or titanium	Grade 5 titanium
Display	Wide-angle LTPO3, 2,000 nits	LTPO3, 3,000 nits
Chip and storage	S10; 64GB	S11; 64GB
Heart sensors	Third-generation optical, plus ECG	Health Sensing System
Normal use	Up to 18 hours	Up to 50 hours
Low Power Mode	Up to 36 hours	Up to 84 hours
Charge to 80%	About 30 minutes	About 45 minutes
GPS	L1	Dual-frequency
Cellular	LTE and UMTS	5G RedCap and LTE
Water	50m; depth gauge for snorkeling	100m; dives to 40m
US launch price	$399	$799

The new heart sensors belong to Ultra 4

Series 10 uses a third-generation optical heart sensor and has neither the Health Sensing System nor a readiness score. Ultra 4 checks your heart rate in the background every five seconds and heart rate variability as often as every five minutes, then turns that into a 0–10 readiness score each day. Apple’s 60× and 24× figures for those readings compare Ultra 4 with Ultra 3, not with Series 10.

Series 10 still covers the core health features. It has ECG and Blood Oxygen (available by region, and not diagnostic), plus sleep apnea notifications for people 18 and older, a feature Apple offers on Series 9 or later and Ultra 2. Series 10 launched without a Sleep score or hypertension notifications; Apple has since added some of those features to older watches through software updates.

Charging fast against lasting long

Apple rates Series 10 for 18 hours of normal use and 36 in Low Power Mode, and gives it no outdoor workout rating. What it does well is charge: 80% in about 30 minutes, 8 hours of normal use from 15 minutes and 8 hours of sleep tracking from 8 minutes. If you top up every morning, that fits a daily routine better than Ultra 4’s 45 minutes to 80%.

Ultra 4 is rated for up to 50 hours, or 84 in Low Power Mode, plus 18 hours in an outdoor workout, 25 in Extended Workout and 45 in Max Extended Workout, which covers outdoor running, walking and hiking with GPS checking your position every second. A 15-minute charge gives it about 18 hours. If you’ll go two days without a charger, Ultra 4 is the one rated for it.

A thinner case and a wide-angle screen

Series 10 was the watch that introduced the wide-angle LTPO3 OLED, which Apple says can look up to 40 percent brighter when you glance at it from the side. It peaks at 2,000 nits and dims to 1, with 374 × 446 pixels (989 square millimeters) on the 42mm and 416 × 496 (1,220 square millimeters) on the 46mm, both at 326 ppi. The front is Ion-X glass on aluminum models and sapphire on titanium.

Ultra 4’s LTPO3 screen is brighter, at 3,000 nits, with 422 × 514 pixels across 1,245 square millimeters. Both are Always-On and refresh once a second with your wrist down; Series 10 brought that to the Series line and Ultra 4 lists the same 1Hz rate, so it’s no reason to upgrade.

The cases are where you’ll feel the difference. Series 10 measures 42 × 36 × 9.7mm or 46 × 39 × 9.7mm. In aluminum with GPS it weighs 30 grams (42mm) or 36.4 grams (46mm), and in titanium 34.4 or 41.7 grams; Apple lists some cellular models as lighter than their GPS versions. Ultra 4 is 49 × 44 × 12mm and about 63 grams, in titanium only. Series 10 fits wrists from 130 to 200mm (42mm) or 140 to 245mm (46mm), and Ultra 4 fits 130 to 210mm.

What Ultra 4 adds outdoors

Ultra 4 has dual-frequency GPS, 5G RedCap cellular (model A3579), an Action Button, a siren, satellite messaging and a 40m dive rating, and Apple rates it for wrist temperatures down to minus 20 degrees Celsius and altitudes up to 9,000 meters. Both watches are IP6X dust resistant, but Series 10 has no MIL-STD rating, and Apple specifies it for 0 to 35 degrees Celsius and up to 3,000 meters of altitude.

Series 10’s GPS is single-frequency L1, with GLONASS, Galileo, QZSS and BeiDou, and its cellular models use LTE and UMTS. Its 50-meter water rating covers swimming and snorkeling but not scuba; for snorkelers it has a depth gauge, a water temperature sensor and Oceanic+ support (a subscription), with no stated depth limit such as 6 meters. Hiking gets a compass, waypoints, Backtrack, offline maps, U.S. topographic maps and curated hikes in 63 national parks, and running metrics include stride length, ground contact time and vertical oscillation. Staying on Series 10 doesn’t cost you maps; it costs you dual-frequency GPS and the long GPS workout ratings.

Everything else

Series 10 runs S10 with a 4-core Neural Engine and 64GB, against S11 and 64GB in Ultra 4. It supports double tap but not wrist flick, which arrived with Series 11. It has Wi-Fi 4, though Apple doesn’t break out 2.4GHz and 5GHz the way it does for later Series models, plus Bluetooth 5.3 and a second-generation ultra-wideband chip. Apple Watch For Your Kids works on cellular models, though a child’s watch doesn’t get every feature. There’s no Action Button to map a flashlight to, and Apple lists no flashlight for it.

Series 10 ships with one band and a USB-C magnetic charger. Apple counts it as carbon neutral with certain bands and says more than 30 percent of its material is recycled or renewable, with cases of 100 percent recycled aluminum or 95 percent recycled titanium. Ultra 4 is 45 percent recycled content, including all of the titanium in its case and recycled cobalt and lithium in the battery.

Price

Series 10 launched at $399 and Ultra 4 at $799. Before you buy a Series 10, look at Series 12: it also starts at $399 and adds the Health Sensing System that Series 10 lacks. Series 10 is a good buy only at a clear discount, and one priced anywhere near Ultra 4 is the wrong deal, so check apple.com before you buy.