My Apple Watch ultra continuously locks itself while on my wrist do not know why.

Hey Aarmentajr,

Thanks for posting in Apple Support Communities. It sounds like your Apple Watch may not be detecting your wrist. You can try disabling wrist detection or adjust the band for a better fit. Check out the following from Lock or unlock Apple Watch - Apple Support.

Lock automatically

By default, your Apple Watch locks automatically when you’re not wearing it. To change the wrist detection setting, do the following.

1. Open the Settings app  on your Apple Watch.

2. Tap Passcode, then turn Wrist Detection on or off.

Turning off wrist detection affects these Apple Watch features:

• When you use Apple Pay on your Apple Watch, you’ll be prompted to enter your passcode when you double-click the side button to authorize the payment.

• Some Activity measurements are unavailable.

• Heart rate tracking and notifications are turned off.

• Apple Watch will no longer automatically lock and unlock.

• Apple Watch wonʼt automatically make an emergency call even after it has detected a hard impact fall.

Take care.