Hi
If I take bus 604 to go to st louis center from basel center, do I need a 2 zone ticket or some special cross border ticket

Thanks

You need a special ticket -- the 603/604 busses aren't covered by the Basel tickets. You can buy the ticket from the driver on the bus, either in CHF or in EUR. From memory, it's cheaper to purchase it in EUR.

I believe if you have a "three country ticket" (day ticket or whatever) then you can use it on that bus.

However, unless you were going to buy a day ticket anyway, it's cheaper just to bung the driver whatever he wants in Euros as you get on. I didn't know you could pay in CHF as well; hats off to VI for his knowledge.