Jun 23, 2019 - 4:41 PM
Viator.com is not a tour operator but an intermediate/retailer for lots of travel related products from countless tour operators. That includes guided tours but also tickets for self guided trips, multi-day tours, etc.. Their guided one-day tours are often partly by motor coach. Their tickets are mostly for people without a pass, but there might be exceptions.
In any case, they are only one of the purchase options, so if you can't find what you're looking for, then please have a look at our price and packages pages, where you'll find other retailers as well. Two examples: