In Don't Starve Shipwrecked there are four new exclusive playable characters. Listed below is a brief description of each along with their strengths, weaknesses and how to unlock them.
Walani
Walani becomes unlocked when you have 2240 XP. She is a surfer with a relaxed personality who carries a custom Surfboard that does not require hands to row which makes it useful for exploration during the early stages of the game. As well as being able to dry faster she also gets hungry slightly faster than normal and effects over time on her Sanity are slightly weaker. Her maximum Health is only 120 but her Hunger is 200, making up for the faster drain to it.
Warly
Warly becomes unlocked when you have 2560 XP. He starts the game with a Portable Crock Pot that enables him to cook exclusive recipes, and a Chef Pouch that allows him to keep food for longer than normal. The Portable Crock Pot can be carried around and placed at any time which means Warly does not have to build a Crock Pot in order to cook his meals. Warly gets hungry 33% faster than normal, but he has a maximum Hunger of 250 to make up for it. Warly's chef background and appetite in French cuisine means he dislikes raw or cooked ingredients, preferring and gaining more benefits from Food cooked in a Crock Pot.
Wilbur
Wilbur is an intelligent monkey that cannot speak human languages and is considered king of monkeys. Wilbur can be found on a Raft in the Ocean, usually around the borders between the deep and shallow waters surrounding an island. In order to unlock Wilbur you must return his Tarnished Crown to him. Wilbur gains Sanity when eating Bananas and will automatically produce Manure once every few days which he can throw at his enemies. Wilbur moves slower, but starts running after continuously moving for three seconds to a speed of 8 which is 33% faster than normal. Wilbur has lower maximum Health and Sanity than normal, but higher Hunger, which drains faster when he's running. As their king, Prime Apes are considered permanently befriended to Wilbur and will not harass him.
Woodlegs
Woodlegs is a pirate captain with two peg legs and is accustomed to living a life at sea, whenever he is on land he loses sanity at a rate of -4.8/min. He loves treasure and has a hat that enables him to find it, he also has a slow but powerful pirate boat which he can craft from the start of the game. Woodlegs has a lower than default maximum Sanity which makes his sanity difficult to manage when going for a traditional permanent camp playstyle. Woodlegs is locked in a cage that is found in the Volcano which is unlocked by finding three keys.
Woodslegs is the most difficult of the exclusive characters to unlock, listed below is how to obtain the three keys to unlock his cage.
Iron Key
This is dropped by the Quacken only once.
Golden Key
This key is received randomly from the Yaarctopus upon trading.
Bone Key
This key is available on chance by fishing up a Watery Grave. Each dug grave in the vicinity gives the player a higher chance of finding the key.