Does the SIM card expire?

No, the SIM card does not expire. However, we recommend referring to the general terms and conditions, which can be found at the following link: https://www.thingsmobile.com/terms-and-conditions

In particular, section (4) states:

"...Things Mobile has the right to deactivate SIM Cards if they have not been active for more than twenty-four consecutive months. At the expiration of the twelfth month from the last business relationship, Things Mobile shall inform the Customer of the deactivation of the SIM Card(s), allowing the reactivation of the service on the same number, without any additional charges for the Customer and, where possible, within forty-eight hours of their request."