Yes, it is. Diving is safe on all sides of Mauritius. The island is almost completely surrounded by a halo of coral that protects many of its bays and coves. The inside of that barrier reef is very shallow and calm which makes for some very good locations for beginner divers to snorkel in placid lagoons and shallows full of fish. Advanced divers can dive in stronger currents and rough seas or shark-infested waters.