S.S. Aqua

The S.S. Aqua (高速船アクア号 Fast Ship S.S. Aqua) is a ferry service that runs between Johto and Kanto. It doesn't run as often as the Magnet Train, the only other method of transportation between Johto and Kanto other than using Fly. It travels between Olivine City and Vermilion City. A player can only travel on the S.S Aqua after defeating the Johto League.

In HeartGold and SoulSilver, the captain of the ship implies that the S.S. Aqua travels to Sinnoh, as he mentions finding plates there. However, the ship does not appear in any of the games that take place in the Sinnoh Region.