Bicycles are the standard way to explore Hateruma. Rental shops operate near the ferry port and the rates are low. The island is small enough that you can cover most of it in a half-day ride: the beach, the observatory, the southern monument, and the gusuku ruins are all reachable by bicycle on the island's quiet roads.
A small number of taxis operate on the island, primarily for elderly residents. There is no bus service. Cycling around the coastal perimeter road takes around two hours at a gentle pace.