When you set up a new Apple Watch, you will choose a four-digit passcode to access the device (if you want to have a passcode activated). Once set up, you must enter this passcode to see anything on the watch face when it isn’t on your wrist, or when you first put it back on your wrist after charging. This is for security purposes so someone can’t grab your watch and access your personal health information, messages, and more. What happens if you decide you want to change the passcode because you think a nosy co-worker saw you input yours or your child has figured it out and you don’t want them reading your personal messages? It’s easy to change the Apple Watch passcode.