The only way that you can get a Cloyster on your Emerald game is if you trade it from FireRed or XD.
you can't
The only way to get Cloyster is to evolve Shellder.
Cloyster evolves from Shellder by using a Water Stone on it.
Cloyster cannot evolve.
For Cloyster its basic
There is a rumor you can find one in whirl islands, but the sure way to go is catch a sheller and use an water stone on it, im trying to find a shiny shelder atm shiny cloyster would be epic
i just kept fishing every spot of water but cloyster mostly shows up in pallet town near the water with super or good rod
To find Cloyster in Pokemon Diamond, you need a super rod, which you find at the Fight Area, after you got the National Dex Then you can go to these areas to fish him: (you need Shellder first) Valley Windworks, Fuego Ironworks, and Route 205. After you find him you evolve him with a Water Stone. Hope i helped :)
Get a shellder then use a water stone on it and it will evolve into a cloyster.
find a shellder in the water of pallet town then give it a water stone
Catch a shellder then use a water stone on it it will evolve into cloyster.
You can't find a Dawnstone in Pokemon Emerald