Route 206. You must use the Poke Radar. It's pretty rare but it's there.
In Pokemon Diamond and Pearl, Baltoy evolves into Claydol at Level 36.
You need to catch and evolve a Baltoy, or trade from another version. You can find Baltoy's on Route 206 using a PokéRadar.
Baltoy is a Ground and Psychic type pokemon.
Baltoy evolves at level 36.
Baltoy > lvl 36 > Claydol
Baltoy is a Ground/Psychic Pokemon with the ability to levitate and a 33.3% catch rate. Beginning at level 36, Baltoy can evolve into Claydol.
Baltoy is unavailable in Pokemon Black & White. To obtain Baltoy, you would have to find one in the Dream World or trade with someone who has it on Black & White 2
Baltoy can be found on Route 3 if they are swarming there. To check what Pokemon is currently swarming, listen to Professor Oak's Pokemon Talk, he will say what Pokemon is swarming where.
You can Catch them in on the route 206 in Pokemon diamond, pearl, and platinum but is quite rare to catch so you should use a pokeradar in the grass.
I do not have Pokemon Arena, but in the other Pokemon games Baltoy evolves at level 36 into Claydol. Hope this helps! Master
It is ok, when evolved
Baltoy is #343 in the national pokedex, and it is a Ground-Psychic type Pokemon.