As this is a small island with limited tourist development, there are few available activities in Donoussa. Apart from swimming in secluded beaches and hiking to go from one beach to the other, there are no other things to do in Donoussa island.
Hiking on the island is actually the main way to get around. Paths will lead you to hilltops with great view to the Aegean Sea, small chapels and small beaches. Free camping on the beach is frequently practised in Donoussa due to the limited number of tourists.