The Apple Watch Ultra 4 is Apple’s most capable and rugged smartwatch, built for extreme endurance, outdoor exploration, and aquatic sports. Engineered with a 49mm Grade 5 titanium chassis, the Ultra 4 features a flat sapphire crystal display, a customizable Action button, and an upgraded sensor suite driven by the Apple S11 chip.

Operating on watchOS 27, the Ultra 4 introduces Apple’s upgraded Health Sensing System, providing continuous passive heart rate sampling and expanded Recovery HRV metrics alongside on-device Audio Intelligence tools. With up to 50 hours of standard battery life and emergency satellite connectivity, it combines high-performance sports tracking with critical safety features.

Technical Specifications

Design & Build

• Case & Material: 49mm Grade 5 Titanium case available in Natural Titanium and Black Titanium finishes.

• Display: Always-On Retina LTPO3 OLED display (422 × 514 pixels, 326 ppi) covered by a flat sapphire crystal front glass.

• Brightness: Up to 3,000 nits peak outdoor brightness down to 1 nit minimum brightness.

• Physical Controls: Customizable Action button, Digital Crown with haptic feedback, and dedicated side button.

• Dimensions & Weight: 49 mm × 44 mm × 12 mm; 63.0g (Natural) / 63.1g (Black).

• Durability Ratings: 100m water resistance (WR100), IP6X dust resistance, EN13319 recreational dive computer rating (up to 40m depth), and MIL-STD 810H testing.

Performance & System Hardware

• System-in-Package: Apple S11 SiP with a 64-bit dual-core processor and 4-core Neural Engine.

• Storage Capacity: 64GB onboard storage.

• Wireless & Location: Precision dual-frequency GPS (L1 and L5), 2nd-generation Ultra Wideband (UWB) chip, Wi-Fi 4 (2.4GHz/5GHz), Bluetooth 5.3, and 5G RedCap / LTE cellular connectivity.

Health, Fitness & Sensing System

• Health Sensing System: Upgraded optical heart sensor with continuous 5-second passive sampling, 2nd-generation electrical heart sensor (ECG), blood oxygen sensor, and wrist temperature sensor.

• Biometric Insights: Dual-metric HRV tracking (Recovery HRV and Overall HRV), daily Readiness score, sleep tracking with sleep apnea detection, and cycle tracking with retrospective ovulation estimates.

• Aquatic & Outdoor Tools: Integrated depth gauge and water temperature sensor, 86-decibel emergency siren, offline topographic map support, and custom Backtrack GPS waypoints.

Battery & Power Management

• Everyday Battery Life: Up to 50 hours of standard usage on a single charge.

• Low Power Mode: Up to 84 hours of extended usage.

• Workout Battery Performance: Up to 18 hours of outdoor workout tracking with continuous GPS and heart rate, up to 25 hours in Extended Workout mode, and up to 45 hours in Max Extended Workout mode.

• Fast Charging: Recharges from 0% to 80% in approximately 45 minutes; 15 minutes of charging yields up to 18 hours of normal use.