What do you mean by 'the right to substitute properties'?

Most of the resorts in the Yasawa and Mamanuca Islands are quite small and capacity is limited. Where we specify particular resorts, chances are, you will stay at that resort. BUT ... on occasion they may be full for the dates that you want to stay there.

Why? Reservation systems in the Yasawas aren't always that flash and we rely on phone calls rather than automated reservation systems. This means that when you book any multi-island stay package we reserve the right to put you in another property. The new resort will be of a similar standard to the original and you'll have just as good a time. Occasionally we may even have to swap the order of the nights around or put you on a different island but in all cases we’ll provide you with a similar experience.