The Shoal Shell is an item in Generations III and IV. In Generation III, four Shoal Shells can be be given to the man in Shoal Cave along with four Shoal Salts to receive a Shell Bell. In Generation IV, the Shoal Shell does nothing.

Location

Generation III

In Generation III, the Shoal Shell can be found at high tide in Shoal Cave.

Generation IV

In Generation IV, the Shoal Shell can't be obtained in-game. Therefore, the only way to get one in Generation IV is to have a Pokémon in a Generation III game hold one and transfer it over via Pal Park.