Screen size
Watch Series 4 Aluminum1.8"
Watch Ultra 3Winner: 2.0"+10%
Quick verdict
Watch Ultra 3 leads the measured specs 7-3.
Measured wins
Watch Series 4 Aluminum
3
spec wins
Ties
4
equal specs
Watch Ultra 3
7
spec wins
Overall winner
Screen size
Technology
Watch Series 4 Aluminum
GSM / HSPA / LTE
Watch Ultra 3
GSM / HSPA / LTE / 5G
2G bands
Watch Series 4 Aluminum
GSM 850 / 900 / 1800 / 1900
Watch Ultra 3
GSM 850 / 900 / 1800 / 1900
3G bands
Watch Series 4 Aluminum
HSDPA 850 / 900 / 2100 / 800 - Europe, Australia, HSDPA 850 / 1700(AWS) / 1900 / 800 - USA, LATAM, Canada, HSDPA 2100 - China
Watch Ultra 3
HSDPA 850 / 900 / 1700(AWS) / 1900 / 2100 - International, China, HK, HSDPA 850 / 1700(AWS) / 1900 / 2100 - USA, LATAM, Canada
4G bands
Resolution
Refresh rate
Peak brightness
Pixel density
equal specsCPU speed
RAM
Storage
Main camera
Front camera
Battery
Wired charging
Weight
Thickness
IP rating
Wi‑Fi
Bluetooth
USB
5G support
NFC
equal specs3.5mm jack
equal specsSD card
equal specsStereo speakers
Watch Series 4 Aluminum
1, 3, 5, 7, 8, 18, 19, 20, 26 - Europe, Australia, 2, 4, 5, 12, 13, 17, 18, 19, 25, 26, 41 - USA, LATAM, Canada, 1, 3, 39, 40, 41 - China
Watch Ultra 3
1, 2, 3, 4, 5, 6, 7, 8, 18, 19, 20, 25, 26, 28, 39, 40, 41, 66 - International, China, HK, 1, 2, 3, 4, 5, 6, 7, 12, 13, 14, 17, 18, 19, 25, 26, 39, 40, 41, 66 - USA, LATAM, Canada
Speed
Watch Series 4 Aluminum
HSPA, LTE
Watch Ultra 3
HSPA, LTE, 5G
5G bands
Watch Series 4 Aluminum
-
Watch Ultra 3
SA/NSA
Announced
Watch Series 4 Aluminum
2018, September. Released 2018, September
Watch Ultra 3
2025, September 09
Status
Watch Series 4 Aluminum
Discontinued
Watch Ultra 3
Available. Released 2025, September 19
Dimensions
Watch Series 4 Aluminum
44 x 38 x 10.7 mm (1.73 x 1.50 x 0.42 in)
Watch Ultra 3
49 x 44 x 12 mm (1.93 x 1.73 x 0.47 in)
Weight
Watch Series 4 Aluminum
36.7 g (1.31 oz)
Watch Ultra 3
61.6 g or 61.8 g (black) (2.15 oz)
Build
Watch Series 4 Aluminum
Glass front, ceramic/sapphire crystal back, aluminum frame
Watch Ultra 3
Sapphire crystal front, ceramic/sapphire crystal back, titanium frame (grade 5)
SIM
Watch Series 4 Aluminum
eSIM
Watch Ultra 3
eSIM
Other
Watch Series 4 Aluminum
50m water resistant ECG certified (region dependent SW application; HW available on all models)
Watch Ultra 3
IP6X certified 100m water resistant (22810:2010) 40m swimproof/diving (EN13319) MIL-STD-810H compliant ECG certified (region dependent SW application; HW available on all models)
Type
Watch Series 4 Aluminum
Retina LTPO OLED, 1000 nits (peak)
Watch Ultra 3
Retina LTPO3 OLED, 3000 nits (peak)
Size
Watch Series 4 Aluminum
1.78 inches
Watch Ultra 3
1.98 inches
Resolution
Watch Series 4 Aluminum
448 x 368 pixels (~326 ppi density)
Watch Ultra 3
514 x 422 pixels (~326 ppi density)
Protection
Watch Series 4 Aluminum
Ion-X strengthened glass
Watch Ultra 3
Sapphire crystal glass
Other
Watch Series 4 Aluminum
3D Touch display
Watch Ultra 3
Wide-angle OLED
OS
Watch Series 4 Aluminum
watchOS 5.0, upgradable to watchOS 10.6.1
Watch Ultra 3
watchOS 26, upgradable to watchOS 26.2.1
Chipset
Watch Series 4 Aluminum
Apple S4
Watch Ultra 3
Apple S10
CPU
Watch Series 4 Aluminum
Dual-core
Watch Ultra 3
Dual-core
GPU
Watch Series 4 Aluminum
PowerVR
Watch Ultra 3
PowerVR
Card slot
Watch Series 4 Aluminum
No
Watch Ultra 3
No
Internal
Watch Series 4 Aluminum
16GB 1GB RAM
Watch Ultra 3
64GB
Other
Watch Series 4 Aluminum
No
Watch Ultra 3
No
Loudspeaker
Watch Series 4 Aluminum
Yes
Watch Ultra 3
Yes, with dual speakers (86-decibel)
3.5mm jack
Watch Series 4 Aluminum
No
Watch Ultra 3
No
WLAN
Watch Series 4 Aluminum
Wi-Fi 802.11 b/g/n
Watch Ultra 3
Wi-Fi 802.11 b/g/n, dual-band
Bluetooth
Watch Series 4 Aluminum
5.0, A2DP, LE
Watch Ultra 3
5.3, A2DP, LE
Positioning
Watch Series 4 Aluminum
GPS, GLONASS, GALILEO, QZSS
Watch Ultra 3
GPS (L1+L5), GLONASS, GALILEO, BDS, QZSS
NFC
Watch Series 4 Aluminum
Yes
Watch Ultra 3
Yes
Radio
Watch Series 4 Aluminum
No
Watch Ultra 3
No
USB
Watch Series 4 Aluminum
No
Watch Ultra 3
No
Sensors
Watch Series 4 Aluminum
Accelerometer, gyro, heart rate, barometer
Watch Ultra 3
Accelerometer, gyro, heart rate, barometer, always-on altimeter (-500m to 9000m), compass, SpO2, VO2max, temperature (body), temperature (water)
Other
Watch Series 4 Aluminum
Natural language commands and dictation (talking mode)
Watch Ultra 3
Temperature sensing (0.01˚ accuracy) Depth gauge (±1m accuracy) Ultra Wideband (UWB) support (gen2 chip) Emergency SOS via satellite
Type
Watch Series 4 Aluminum
Li-Ion 292 mAh (1.12 Wh), non-removable
Watch Ultra 3
Li-Ion 599 mAh
Charging
Watch Series 4 Aluminum
Wireless
Watch Ultra 3
Wireless, 0-80% in 45 min
Colors
Watch Series 4 Aluminum
Silver, Gold, Space Gray
Watch Ultra 3
Natural, Black
Models
Watch Series 4 Aluminum
A1975, A1976, A2007, A2008, A1977, A1978
Watch Ultra 3
A3281, A3282
Price
Watch Series 4 Aluminum
About 430 EUR
Watch Ultra 3
€ 829.00
SAR
Watch Series 4 Aluminum
-
Watch Ultra 3
1.16 W/kg (head)
SAR EU
Watch Series 4 Aluminum
-
Watch Ultra 3
1.19 W/kg (head)