Pokémon Ruby and Sapphire/Route 134

This route flows into Slateport City and is important for containing the Sealed Chamber, the place where you awaken the 3 Regis (Regirock, Regice, Registeel) You have to dive to get there. You can also find a Carbos and a Star Piece here if you're playing Emerald.

Items

 * Carbos (Emerald only) - west end of the long island
 * Star Piece (Emerald only) - southwest corner island