The submarine belongs to that scientist guy, you're not allowed on, you have to learn dive then find the place they are exploring, but there is a scale model of the sub in the museum.
Catch the submarine Pokémon and beat the crap out of the Elite Four.
he goes to his underwater hideout cave.
Go back to Slateport town. Inside the ferry building, you will find captain stern and the submarine being robbed by Team Aqua.
in your moms belly
Pokemon Ruby has Pokemon that Pokemon Sapphire does not and Pokemon Sapphire has Pokemon that Pokemon Ruby does not.
there a dive area and once you dive there, there youll find the submarine but you really need to look. the entrabce is like entering a cave underwater
go get a life
There is no Pokemon mansion in sapphire.
you will find team aqua in the under water cavern near the dive point in sootopolis
He is not in Pokemon: Sapphire. You will not be able to find him. He is in Pokemon: Diamond, Pokemon: Pearl, and Pokemon: Platinum. You will definitely have trouble finding him in Pokemon: Sapphire.
Evee is not availiable in Pokemon Sapphire.
Any Pokemon in sapphire but you have to migrate