watchOS® 5.3 is available from Apple. Learn about all the updates to watchOS 5.3 on Apple's website, including the impacts to your Apple Watch.
You can update over Wi-Fi, using the Watch app on your iPhone.
Before starting your watchOS update, please make sure:
Learn how to use your device
Apple, Apple Watch, watchOS and Apple Pay are registered trademarks of Apple Inc.
Apple Watch Series 3 requires an iPhone 6 or later with iOS 11.