One of the best places for diving on the east coast and easily accessible on the bus from Maputo (as accessible as anything is Mozambique, anyway), Tofo is an excellent place to spend a few days relaxing after the heat of the city. Ask at your hostel if you want a specific activity but otherwise it’s easy just to wander along the seafront and stop in at any of the offices offering snorkelling or diving. It’s cheap, too, even by African standards.