It is almost exactly in between Sootopolis City and Ever Grande City on your map. Go there and dive underwater. Search around underwater and eventually you should find an underwater cave containing the submarine. When you find the submarine, head to the surface.
get close to moss deep and then dive under the water search for the cave
Catch the submarine Pokémon and beat the crap out of the Elite Four.
After you find the stolen submarine in Pokémon Emerald you must go to Mossdeep city. There you will obtain the HM Dive.
he goes to his underwater hideout cave.
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.
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.
Lieutenant Pimple and the Stolen Submarine - 1914 is rated/received certificates of: UK:U
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