Due to capacities on some of our additional options, you may find that the option is sold out on the booking page, and you need to join the waiting list for that specific trip element.
We recommend if you are interested in that option, you definitely add yourself to the waiting list, because as soon as we are able to either increase the capacity, or another passenger removes that option/cancels their trip, you will be first in line to gain access to that option.
It is really important to note that if you no longer want to be on a waiting list, please log in to your account and remove yourself from the waiting list.