Seasail Merchant

Seasail Merchants sell Boat Passes for the V.S.S. Seaskipper for varying prices and Oak Boats for 2 Emerald Blocks. They are usually located next to the Seaskipper Captain. The Seasail Merchants at the three major docks Nemract, Selchar and Llevigar sell many different Boat Passes, whereas the Seasail Merchants at the minor docks only sell Boat Passes to the three main ports.

Boats
As of 1.14.1, all Boat Merchants were removed from the game. However, you can still buy boats at Seasail Merchants. Boats can be summoned in the same way as Horses, and you automatically pick up the boat when you leave it.

All Oak Boats sold by Seasail Merchants have a modifier on them ever since the 1.19 update.

Refunds
As of 1.20.2, players right-click the middle of the boat to select and pay for their destination instead of tossing a pass into a hopper. As such, the Seasail Merchant now buys passes from players instead of selling them. This service is only available at major ports.

Trivia

 * Nodguj Island's Seasail Merchant used to be the only merchant to sell a boat with a modifier, giving +20% Speed during use. This persisted even after Boat Merchants were removed in 1.14.1.
 * Originally, the introduction of the V.S.S. Seaskipper to players was through the Sister City quest. Now it is done through Misadventure on the Sea.
 * In order to reduce lag and fix various bugs, travelling by boat became simulated.This means that boats can't go through lily pads anymore.