Do the SIM cards have expiration dates?
No, the SIM cards do not have expiration dates. However, we recommend that you read the general contract terms and conditions, which you can find here: https://www.thingsmobile.com/terms-and-conditions .
In particular, section 6 establishes that:
“ [...] The Company shall be entitled to deactivate the Things Mobile SIM Card(s) in the event that the Things Mobile SIM Card is inactive for more than twenty-four consecutive months. At the expiration of the twelfth month from the last business relationship, the Company informs the Customer of the deactivation of the Things Mobile SIM Card(s), allowing the reactivation of the service on the same number, through simple procedures and without any additional charges for the Customer, within forty-eight hours from their request, save for exceptional cases.”