The phone number to check the balance of a NetSpend prepaid card with customer service is 1 866 387 7363 (or 1 86 NETSPEND), as of 2015. Alternatively, it is possible to text "BAL" to 22622, the balance is texted back almost immediately.
The customer service number is available at any time of the day, any day of the week. However, this is not free of charge, as of 2015, and a fee is charged. It is possible to check the card balance at an ATM machine, but this is also subject to a fee. The NetSpend website also provides a balance-checking facility.