Koror is Palau's main island and the country's commercial heart — the place where nearly everyone stays, eats, and gears up for the underwater adventures that make Palau famous. It is a compact, walkable town with a mix of Japanese colonial relics, concrete shophouses, and dive shops lining the main road. Don't mistake busyness for charm: Koror is a functional base, not a destination in itself.
The real draw is what surrounds it. The Rock Islands stretch to the south — some 200 limestone outcroppings draped in jungle, with lagoons of implausible turquoise. The giant island of Babeldaob lies just to the north, connected by the Compact Road and largely undeveloped. Most divers base themselves in Koror and go out by boat each morning.
Within Koror, the Belau National Museum is worth an hour of your time. It has a solid collection covering Palauan cultural history, traditional storyboards, and the islands' complicated colonial past — ruled in turn by Spain, Germany, Japan, and the United States before independence in 1994. The nearby Etpison Museum has more artefacts and some good underwater photography. The Palau International Coral Reef Center is a useful primer before any dive trip, and the jungle-overgrown ruins of the Nan'yō Shrine are a quiet reminder of the long Japanese colonial period. Day trips to Jellyfish Lake leave from the Malakal marina, which is also the liveliest part of town for nightlife.