Corsola locations — where to catch

In Sinnoh (Diamond, Pearl & Platinum)

Brilliant Diamond / Shining Pearl (Gen 8): Sea Route 230
Sword / Shield (Gen 8): Isle Of Armor Caves, Giant's Mirror, South Lake Miloch, Stony Wilderness, Watchtower Ruins
Ultra Sun / Ultra Moon (Gen 7): Route 9, Alola Route 9, Hauoli City, Melemele Sea, Poke Pelago
Sun / Moon (Gen 7): Route 9, Alola Route 9, Melemele Sea
Omega Ruby / Alpha Sapphire (Gen 6): Ever Grande City, Route 128, Pacifidlog Town, Underwater
X / Y (Gen 6): Friend Safari, Kalos Route 12
Black 2 / White 2 (Gen 5): Hidden Grotto, Humilau City, Unova Route 18, Route 18
Black / White (Gen 5): Undella Town, Unova Route 13