Apple Watch Series 12 vs Apple Watch Ultra 4
4 questions both answer, side by side. Every answer is backed by the dated sources at the bottom.
Side by side
Can a smartwatch work without your phone nearby?
GPS + Cellular models of Apple Watch Series 12 support 5G (RedCap) and LTE.
Good to know: Needs a carrier plan; costs vary.
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?
Apple Watch Series 12 has Siri powered by Apple Intelligence.
Good to know: Maker's description.
Apple Watch Ultra 4 has Siri powered by Apple Intelligence.
Good to know: Maker's description.
How long does a smartwatch battery last?
Apple rates Series 12 at up to 24 hours of normal use and 38 hours in Low Power Mode; 15 minutes of charging gives up to 12 hours.
Good to know: Maker's figures.
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?
Apple Watch Series 12 works with an iPhone; Apple lists iPhone 11 or later on iOS 26 for its watchOS 26 features.
Good to know: Apple's requirement is a footnote on its watchOS 26 features.
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)
Apple Watch Series 12 tech specs (read Oct 23, 2026): up to 24 hours of normal use, up to 38 hours in Low Power Mode, up to 10 hours of workout tracking; 15 minutes of charging gives up to 12 hours. GPS + Cellular models support 5G (RedCap) and LTE. Siri powered by Apple Intelligence. Apple's notes list iPhone 11 or later on iOS 26 for its watchOS 26 features.
Read the sourceApple 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