Compare · Smartwatches

Apple Watch SE 3 vs Apple Watch Ultra 4

4 questions both answer, side by side. Every answer is backed by the dated sources at the bottom.

AppleWatch SE 3Apple's lower-priced watch with Siri powered by Apple Intelligence; up to 18 hours of battery.Last checked Oct 21, 2026AppleWatch Ultra 4Apple's rugged watch with up to 50 hours of battery, 5G and satellite antennas.Last checked Oct 21, 2026

Side by side

Can a smartwatch work without your phone nearby?

Watch SE 3
Yes

GPS + Cellular models of Apple Watch SE 3 support 5G (RedCap) and LTE.

Good to know: Data plan required; cellular models only.

Watch Ultra 4
Yes

Apple Watch Ultra 4 supports 5G (RedCap) and LTE, with antennas for cellular and satellite.

Good to know: Data plan required; 5G only in select markets.

Can you talk to an AI assistant on your smartwatch?

Watch SE 3
Yes

Apple Watch SE 3 has Siri powered by Apple Intelligence.

Good to know: Maker's description.

Watch Ultra 4
Yes

Apple Watch Ultra 4 has Siri powered by Apple Intelligence.

Good to know: Maker's description.

How long does a smartwatch battery last?

Watch SE 3
Yes

Apple rates Apple Watch SE 3 at up to 18 hours of normal use and 32 hours in Low Power Mode.

Good to know: Maker's figures.

Watch Ultra 4
Yes

Apple rates Apple Watch Ultra 4 at up to 50 hours of normal use and 84 hours in Low Power Mode; 15 minutes of charging gives up to 18 hours.

Good to know: Maker's figures.

Which phone does a smartwatch need?

Watch SE 3
Yes

Apple Watch SE 3 requires an iPhone 11 or later with iOS 27 or later.

Good to know: Apple lists iPhone models only.

Watch Ultra 4
Yes

Apple Watch Ultra 4 requires an iPhone 11 or later with iOS 27 or later.

Good to know: Apple lists iPhone models only.

How we know (2 sources)
  1. undated, read AppleFrom the company

    Apple Watch SE 3 tech specs (read Oct 24, 2026): up to 18 hours of normal use, up to 32 hours in Low Power Mode; 15 minutes of charging gives up to 8 hours. GPS + Cellular models support 5G (RedCap) and LTE; data plan required. Siri powered by Apple Intelligence. Requires iPhone 11 or later with iOS 27 or later.

    Read the source
  2. undated, read AppleFrom the company

    Apple Watch Ultra 4 tech specs (read Oct 24, 2026): up to 50 hours of normal use, up to 84 hours in Low Power Mode, up to 18 hours of workout tracking; 15 minutes of charging gives up to 18 hours. Supports 5G (RedCap) and LTE, with cellular/satellite antennas; data plan required. Siri powered by Apple Intelligence. Requires iPhone 11 or later with iOS 27 or later.

    Read the source