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Smartwatches / Compare

Apple Watch Series 8 vs Apple Watch Ultra 3

66 of 141 fields differ

Download CSVDownload JSON
  • 34 different values
  • 32 known for one only
  • 39 the same
  • 36 missing for both

Biggest differences

Each bar uses the scale of all 101 smartwatches.

  1. Peak brightnessA: 1,000nitsB: 3,000nitsWatch Ultra 3 is 3 times higher.
  2. Battery lifeA: 18hB: 42hWatch Ultra 3 is 24 h higher.
  3. Water resistanceA: 5ATMB: 10ATMWatch Ultra 3 is 5 ATM higher.

Size, drawn to scale

Front and side.

Weight

0 to 80 g

Weight (case only)
A31.9g
B61.6g

All 150 fields

Every value links to where we found it.

AApple Watch Series 8
BApple Watch Ultra 3

General

8 of 10 differ
GTIN / EAN
Not available
Not available
Predecessor
Not available
OS updates promised
Not available
Not available
Security updates until
Not available
Not available

Case

7 of 8 differ
Case size
Case material
Weight with strap
Not available
Not available

Durability

5 of 8 differ
Max dive depth
Not available
MIL-STD-810
Not available
MIL-STD-810 tests
Not available
Altitude, High temperature, Low temperature, Temperature shock, Immersion, Freeze with thaw, Ice and freezing rain, Shock and vibration1Maker product pagesupport.apple.com/en-us/125095Read 5 October 2026

Display

8 of 14 differ
Screen size
Not available
Not available
Max refresh rate
Not available
Not available
Min refresh rate
Not available
Peak brightness

Platform

5 of 15 differ
Software
Not available
Not available
Process
Not available
Not available
CPU configuration
Not available
Not available
Max CPU clock
Not available
Not available
GPU
Not available
Not available
Low-power coprocessor
Not available
Not available

Memory

2 of 2 differ
RAM
Not available
Storage

Health sensors

2 of 8 differ
Body composition sensor
Not available
Not available
Skin conductance (EDA)
Not available
Not available
Medical clearances
Not available

Motion and environment sensors

5 of 9 differ

Health and fitness

3 of 5 differ
Fitness features
Sport profiles
Not available
Not available
Dive modes
Not available
Not available

Safety

1 of 6 differ
Emergency SOS
Emergency siren
Not available
Not available
Dedicated LED flashlight
Not available
Not available

Positioning

3 of 3 differ
Positioning
Offline maps
Not available

Connectivity

6 of 15 differ
Bluetooth
Not available
Wi-Fi
Not available
Cellular
4G bands
Not available
5G bands
Not available
Satellite
Not available
Emergency SOS, Messaging, Location sharing1Maker product pagesupport.apple.com/en-us/125095Read 5 October 2026Safety and footnote 12. Emergency SOS, Messages and Find My supported in eligible regions. Messages and Find My require carrier plan, SMS requires powered-on online paired iPhone. Two free years after activation.19Maker product pagesupport.apple.com/en-us/125128Read 8 October 2026Exact support for Ultra 3 and later: Find My Send Location is a manual update available once every 15 minutes, outside cellular/Wi-Fi coverage. An active carrier plan on the watch is required. Configure Share My Location and intended recipients before going off-grid. A clear view of sky/horizon is required. Nearby paired iPhone in Airplane Mode prevents satellite use. Free for 2 years after activation, not an unlimited free-service promise. Published availability includes Australia, Austria, Belgium, Canada, France, Germany, Ireland, Italy, Japan, Luxembourg, Mexico, Netherlands, New Zealand, Portugal, Spain, Switzerland, UK and US. Luxembourg requires carrier activation in another country. Mexico needs watchOS 26.0.1+. Carrier support and purchase-country exclusions remain applicable. This is distinct from live_tracking and messaging.20Maker product pagesupport.apple.com/en-us/123924Read 8 October 2026Connect to a satellite explicitly covers Ultra 3 and later, supplied by Globalstar or its partners. Satellite services are not offered on units purchased in Armenia, Belarus, China mainland, Hong Kong, Macao, Kyrgyzstan, Kazakhstan or Russia. Region availability, open-sky conditions and activation apply. Find My and Messages require a carrier plan. Only satellite location_sharing is newly added.
ANT+
Not available
Not available

Audio

1 of 4 differ

Controls

3 of 5 differ
Rotating bezel
Not available
Not available

Battery and charging

4 of 13 differ
Claimed battery life
Smartwatch mode (claimed)
18h
42h
AOD battery life (up to)
Not available
Not available
GPS mode (claimed)
Not available
Not available
Solar charging
Not available
Not available
Charging guidance
Not available
Not available
Max charging power (watch)
Not available
Not available
Fast charging
Quick charge claim
Not available
Full charge time (claimed)
Not available
Not available

Measured

None of 4 known
Peak brightness (measured)
Not available
Not available
Battery life (measured)
Not available
Not available
Battery tests (measured)
Not available
Not available
Full charge time (measured)
Not available
Not available

Strap

2 of 6 differ
Lug width
Not available
Not available
Strap system
Not available
Strap material
Not available
Not available
Strap
Not available
Not available
Strap sizes
AApple Watch Series 8
Not available

Regulatory

None of 3 known
FCC ID
Not available
Not available
SAR limb (US)
Not available
Not available
SAR limb (EU)
Not available
Not available
Other certifications
Not available
Not available

In the box

1 of 2 differ

Warranty

None of 1 known
Manufacturer warranty (source market)
Not available
Not available

Both are also in the API. Back to all smartwatches.