How to Choose a PIN for Apple Watch
While not mandatory — unless you use Apple Pay to buy goods or services through your smartwatch — those who use Apple Watch can set up a personal identification number (PIN) in case the watch is lost or stolen. (Some people call it a passcode instead of a PIN, but it’s the same thing.)
It might not provide much comfort for those who break the bank on the top-of-the-line 18-karat gold Apple Watch Edition (!), but it still means no one can access your information or shop via Apple Pay.
Just like with an iPhone, iPad, or iPod touch, if the Apple Watch’s PIN option is activated, you have to enter the four-digit numeric code every time you put the watch back on. Apple Pay requires skin contact and the PIN.
Wait, how does Apple Watch “know” if someone is taking the watch off or putting it on? It’s because of the smartwatch’s internal sensors that touch your skin.
As with a lost iPhone, you can log on to iCloud, log in with your details, and remove your credit and debit cards to prevent the watch from falling into the wrong hands.)
Bottom line: You may want to set up a passcode on your Apple Watch — even if you don’t activate Apple Pay.
And, of course, you should also have a PIN set up on your iPhone. Remember, Apple Watch doesn’t store much information, so protecting the data on your phone is even more important.