The main settlement on Karimunjawa Island, around the small harbour, is the only place on the archipelago with restaurants, ATMs, dive shops, and reliable mobile signal. A central square (Alun-Alun) comes alive in the evening with grilled-fish stalls, satay vendors, and locals on motorbikes.
The mosque, the small mausoleum of Sunan Nyamplungan, and the fish market are worth a wander. Everything else closes by 9 p.m. — when the generator goes off, you sleep.