The Apple Watch Ultra 4 is built for athletes, adventurers and anyone who demands more from their smartwatch. Multi-day battery life, a rugged titanium case and a sapphire crystal display are ready for challenging environments. Precision dual-frequency GPS delivers highly accurate tracking, while the most accurate heart rate sensing in a wearable helps provide deeper insights into performance, stress and recovery. Advanced training features including Pacer, Heart Rate Zones, Custom Workouts and training load help you get more from every session. Plus, Siri AI and Audio Intelligence make it easier to stay connected and get things done throughout the day.Multi-day battery life - Ultra 4 is a smartwatch with ultramarathon battery stamina, perfect for runners to go the distance — with up to 45 hours of Max Extended Workout tracking. And you can fast charge in just 15 minutes for up to 18 hours of use.Stay closer to your heart health - The most accurate heart rate sensing in a wearable, Ultra 4 now measures HRV as often as every five minutes for insights on stress and recovery, and background heart rate readings every five seconds.A full-featured health tracker - Better understand your body with advanced health insights. View your overnight health metrics with the Vitals app and get a daily sleep score, track your menstrual cycle and take readings of your blood oxygen.Check your readiness for the day - Know when to rest or put yourself to the test. The readiness experience gives you one clear score and can help you determine your capacity to take on the day by analysing your recent activity, vitals and sleep.Ultimate running and workout companion - A superior fitness tracker for distance running, triathlons, mountain biking, strength training and more. Ultra 4 has precision dual-frequency GPS, Pacer, Heart Rate Zones, Custom Workouts, training load and more.Keep help close at hand - A smartwatch that puts your safety first. Ultra 4 can detect a hard fall or serious car crash. If you don't have mobile service or Wi-Fi, built-in satellite communications let you text emergency services to get help.Siri AI and Audio Intelligence - Using just your voice, engage in natural, back and forth conversations, brainstorm ideas and more with Siri AI. Audio Intelligence helps catch what you missed and summarise conversations with Live Rewind and Siri Recap. Siri AI is rolling out in English. Some Audio Intelligence features coming in beta late 2026. Usage limits may apply.Rugged and ready to go - Ultra 4 is built for extreme environments with a tough titanium case and a strong sapphire crystal display. Water resistant up to 100m, this smartwatch is great for swimmers, divers and fans of high-speed water sports.The freedom of cellular - With just your smartwatch, you can take and make calls, stream music and podcasts, and listen with your AirPods — even without your iPhone.Please note:- The Vitals app is for wellness purposes only and not for medical use.- The Cycle Tracking app should not be used for birth control or to diagnose a health condition. Cycle deviation notifications inclusive of perimenopause are for people 40 years old or older.- The Blood Oxygen app is for wellness purposes only and not for medical use.