What's the difference between single & double occupancy?

Our pre-designed tour prices are based on double occupancy for each room, meaning we assumed that there would be two people in each room when we calculated the costs of accommodations for each person on the tour. If you'd like to have a room to yourself, you can pay a single occupancy fee to cover the other half of the room. (The fee varies depending on the cost of the accommodations.) If you're traveling alone but would like to avoid paying the single occupancy fee, let us know when you register that you'd be willing to have a roommate and we'll see if anyone else on the tour is looking to share a room. If we can’t find anyone despite your willingness to have a roommate, we'll split the single occupancy fee with you so that you only have to pay half of it.