Hands down, the best place for diving in the entire South is in the clear azure Atlantic waters surrounding the Ilha do Arvoredo, a biological reserve accessible from both Bombinhas  and Florianópolis . Dive operators in Bombinhas offer half-day diving tours to the coral reefs surrounding the southern part of the island, which are teeming with brightly colored fish, dolphins, and sea turtles.
Both Patadacobra (Av. Vereador Manoel José dos Santos, tel. 47/3369-2119, www.patadacobra.com.br ) and Acquatrek (tel. 47/3369-2137, www.acquatrek.com.br ) offer diving courses and half-day outings for divers of all levels. Excursion rates are R$100–150.