I have a t:card for the bus but want to buy an express boat ticket in the app
Currently, you cannot have both a physical t:card for the bus and buy express boat tickets in the AtB app.
If you try to buy an express boat ticket in the app while having a period ticket for the bus using t:card, the AtB app will prompt you to switch from t:card to phone for all your tickets. If you want to switch back to t:card after using the boat ticket, you can easily do so under My profile.