For those who have taken this tour or who are planning to take it, do you know whether we would need to bring a bathing suit?

I am going on the European Inspiration (although not on this particular date) I would advise you to take your bathing suit (swimmers).

You might want to pack that item if you choose the White Water rafting optional activity in Austrian Tyrol. I know I'm going to go on this as, I had so much fun doing it down the Fraser River in Canada on my first Contiki trip.