We don’t cancel a tour if we don’t reach a certain minimum, but we need at least 2 guests to open a group. There would be a surcharge of 25 Euros/person if you end up being the only two clients on a non-private day trip (for some of the city tours, the surcharge is 20 Euros/person). Although this is not likely (especially between April and October), it would be necessary in order to cover the guide fees and other costs that would normally be covered by having more than two clients on the trip. The positive side of the supplement is that you and up getting a private tour at a fraction of the normal private touring price!