SIM PIN

To lock any data stored on it and to prevent data usage while locked.

If you enable the SIM PIN, entering the SIM passcode will be required when powering the iPad on in order to connect to the internet via the cellular data or internet network. The same when turning data or internet access on via the cellular network after turning it off. It is additional protection along with the Passcode Lock feature to prevent unauthorized internet access via the cellular network with your iPad in the event your iPad is lost or stolen, or if the micro-SIM card is removed by someone else for use with another iPad.

Thanks for the "long hand" Allen lol

In the settings...

in cellular data tap Add SIM PIN, then tap SIM PINto set it

Apparently, my iPad came with the PIN already set. I see a CHANGE PIN field rather than an ADD PIN field. Does anyone know the default?

Mine came with a password too. Be careful because you only get three tries to guess this password then it locks you out and you have to call AT&T to get the PUK code. You only get 10 tries on that and the sim card is locked permanently! I had to sign up for a month to be able to unlock it! AT&T girl was nice but admitted to having limited training with iPad. Luckily all I'd well now with trip to the store tonged it replaced.

I'd call AT&T and not try to guess it...