Hello sowmya. I think all the information you're looking for is listed at the BLS website (the boat company for lake Thun and lake Brienz). You can buy your ticket from all BLS counters, such as Thun, Brienz, Interlaken, and many other resorts along both lakes. I'm not sure if tickets can be pre-booked, but you can contact BLS to find out.By the way, could you try not to use capitals only when posting a question, as asked for in our forum rules? Thank you!
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