Where to find dive in Pokemon victory fire?

You can find the HM Dive in Mt. Chimney. Once you get to Mt. Chimney, enter the Pokemon Center and talk to the man near the left counter of the Pokémon Mart inside the Pokémon Center. He will show you how to use Dive and give you the HM. Be sure to have an empty move slot in one of your Pokemon's movesets before talking to him.