You win together by working out the best route through the waters of the Mediterranean completing your missions. Reaching your final destination Great Uncle Harry Island first.
MegaYacht contains a rule book that is well illustrated, highlighting the following:
First Phase
Playing Partners must complete all three Ports on their Mission Card and then land on Great Uncle Harry Island, using Marina Cards at the right time to speed them on their way.
Second Phase
Playing Partners swap boards picking up Mega Cards with two instructions and one Mystery Card to be shared between you. Competition will pick up pace as rivals close in. Stay calm using your cards to make the biggest impact on your rivals possible.