Gift: Nacrene City
You won't find Tirtouga in the wild in this game — you get it as a gift.
Looking for Carracosta? It isn't found in the wild in this game — evolve Tirtouga (Level 37).
For the look, the best colour match is Dive Ball or Net Ball.
Evolution: Tirtouga → Carracosta (Level 37).
Tirtouga in every game · Pokémon Black & White / Black 2 & White 2 interactive map (Unova)