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.
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
Cloyster evolves from Shellder by using a Water Stone on it.
Cloyster cannot evolve.
For Cloyster its basic
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 :)
find a shellder in the water of pallet town then give it a water stone
Get a shellder then use a water stone on it and it will evolve into a cloyster.
Catch a shellder then use a water stone on it it will evolve into cloyster.
You can't find a Dawnstone in Pokemon Emerald