A PIN code acts as a simple password for your Air SIM and is initially set to "0000".
For security, a device will be locked if the wrong PIN code is entered three times. Once a device is locked, you will be asked to enter a PUK (Personal Unlocking Key) or PUC (Personal Unblocking Code) in order to unlock the device.
Many devices have disabled the SIM PIN code feature, so in most cases you should not be required to enter a PIN code.
As the PUK will be different for each operator, you will need to contact Soracom support with the IMSI number of the Air SIM in order to request a PUK.
For your convenience, your IMSI can be automatically added when you initiate a support ticket from the User Console. Simply click the checkbox of the Air SIM device, then click the Support menu and select Contact us.