Castaway Bay is mainly a resort themed board. The only way to earn stars is to reach Donkey Kong's boat. If an unlucky player reaches Bowser's Battle Yacht, Bowser will give then a Ztar to take away one of their Stars (or 20 coins if they don't have one). There is also an area where a player can pay a Shy Guy to ride down the raft and take the shortcut to DK's boat. However, the player must be careful as, sometimes, Bowser will fire cannonballs from his Yacht and if they hit the player, he/she will lose coins.
- Landing on some happening spaces will switch the positions of Donkey Kong's boat and Bowser's Battle Yacht. This can be good or bad depending on how close or far away the player is to that spot.
- Another happening space will start an Ukiki's game which involves collecting coins. Be careful as spiked balls tend to fall down and hit players.
- Castaway Bay's gimmick is very similar to Mario's Rainbow Castle from the original Mario Party. Both boards involve getting the star at a fixed location and after getting the star, the star space switch with Bowser who will either take coins or a star. The Star Space and Bowser can also be changed beforehand by landing on a happening space.