Q: I have read in your site a lot about T-Casual card and understood that we can buy T-Casual at the entrance of RENFE station at the airport. My question is can I buy T-Casual ticket by credit card either at the ticket office or through ticket machines?
A: You can purchase the T-Casual travel ticket with a credit card both at the ticket vending machines and at the manned ticket office. As a matter of precaution, I would consider taking both cash and credit card. Sometimes I've found the automatic vending machines won't function with a credit card for no apparent reason. Some Metro entrances do not have a manned ticket office in which case you will have to use an automatic vending machine. If you purchase your ticket at a manned ticket office remember to have your photographic identification handy because all credit card purchases in Spain, where a cashier is undertaking the transaction, must be accompanied with official photographic ID, e.g. Passport.
A better alternative to the T-Casual might be the Hola Barcelona Travel Card that offers unlimited travel on Barcelona public transport. You won't have to worry about the number of journeys you have left on your T-Casual Ticket or about purchasing a new one that you might not entirely use. With the Hola Barcelona you can travel unlimitedly and worry-free while saving money.
Hola Barcelona Travel Pass