Churaumi Aquarium and northern Okinawa

Churaumi Aquarium sits in Ocean Expo Park on the Motobu Peninsula, roughly two hours by road north of Naha, and is designed around the sea right outside its doors. The centrepiece, the Kuroshio Sea tank, holds whale sharks and manta rays behind an acrylic panel 8.2 metres high and over 22 metres wide. Before reaching it, the route passes shallow reef pools and a coral tank lit by natural sunlight, so walking through feels like moving from the shoreline out into open ocean.

Departures run from Naha or Nago. From Nago, the 3-hour option keeps things simple: the aquarium and nothing else. An 8-hour north combo from either city adds Kouri Island, reached by a long, low bridge over pale turquoise shallows. The 10-hour bus day from Naha goes instead to Nakijin Castle, the ruined stronghold of the old Hokuzan kings, whose curving limestone walls follow the ridge; it is one of the Ryukyu gusuku sites on the UNESCO World Heritage list. Stop order is left to the guide.

Give yourself time in front of the big tank: the whale sharks circle slowly, and the scene changes every few minutes as the rays glide past. Outside, the park has a beach and wide sea views toward Ie Island and its lone peak. Northern Okinawa is hot and humid from May to October, with typhoons possible from summer into autumn; winter is mild and quieter, and Nakijin's early cherry trees flower around late January. A sun hat and water make the castle slope easier.