The Kerama Islands are an archipelago of 36 islands scattered across the East China Sea, roughly 40 km west of Naha, Okinawa's capital. Only four are inhabited: Tokashiki, Zamami, Aka and Geruma. Zamami, Aka and Geruma make up Zamami Village (892 residents as of October 2020, 16.74 km²); Tokashiki, spread across ten islets of its own, is a separate village with 718 residents on the same date. Since 5 March 2014, the surrounding waters and most of the archipelago have been protected as Kerama Shotō National Park.
The sea here has its own name. According to Japan's official tourism agency, the turquoise clarity of "Kerama Blue" comes from a combination of factors: the Kuroshio Current keeps plankton levels low, and because none of the islands has a river of any real size, almost no sediment reaches the water. Beneath that clear surface, the reefs are unusually intact by Japanese standards — 248 coral species have been recorded around the Kerama Islands, most of them in the genus Acropora — and in November 2005 two areas, 120 hectares off Tokashiki and Hanari islands and 233 hectares between Aka and Zamami, were registered under the Ramsar Convention as Wetlands of International Importance.
On land, the islands support one genuinely local species: the Kerama deer (Cervus nippon keramae), an endangered subspecies descended from sika deer introduced in the early 17th century, found today only on Aka, Fukaji, Geruma and Yakabi. Offshore, winter brings humpback whales, which migrate into Kerama waters roughly from January through March or early April — long enough to have built a small whale-watching trade around Zamami and Tokashiki.
The islands' history reaches back to the Ryukyu Kingdom, when Kerama sailors served as navigators on trading ships bound for China. The more recent chapter is harder. On 26 March 1945, the US 77th Infantry Division landed on the Keramas, using them as a staging area days ahead of the main invasion of Okinawa. Two days later, on Tokashiki, 394 residents died in a mass-suicide event carried out under orders from the Japanese military command — an episode historians describe as a precursor to the larger group suicides that followed on Okinawa's main island in the weeks after, and whose exact circumstances remain a subject of historical debate. Zamami saw comparable events in the same period. The islands stayed under US administration until reverting to Japan in 1972.
Access is by ferry from Naha's Tomari Port: the standard ferry takes roughly 1.5 to 2 hours depending on the route, while the high-speed ferry crosses in about 50 minutes to an hour; a small airstrip, Kerama Airport, sits on Fukaji Island, and inter-island ferries connect the group (Zamami to Aka, for instance, in 10 to 15 minutes). Tourism — mostly diving, snorkeling and whale watching — now employs around 92% of Zamami's working population. Swimming season runs roughly May to October; from December to March, sea and air temperatures drop below 20°C and most visitors switch from the beach to whale watching.
One honest caveat is worth adding: according to the Okinawa Churashima Foundation, which monitors reefs across the region, coral communities on Okinawa's main island as well as in the Kerama and Yaeyama islands have declined to unprecedented levels in recent years, attributed to warming waters — a reminder that the clarity of Kerama Blue doesn't make the reefs immune to climate change.
CoveTrip's coverage of the Kerama Islands currently centers on Furuzamami Beach, the largest beach on Zamami and one of the archipelago's most accessible points for reef snorkeling — a practical first stop for anyone weighing up which of the four inhabited islands to base themselves on for a first visit.
By ferry from Naha's Tomari Port: the standard ferry takes 1.5 to 2 hours depending on the route, and the high-speed ferry about 50 minutes to an hour. There is also a small airstrip, Kerama Airport, on Fukaji Island.
Roughly January through March, sometimes stretching into early April — the humpback whales' winter migration season.
Swimming season generally runs May to October. From December to March, sea and air temperatures drop below 20°C, and most visitors switch to whale watching instead.
The archipelago has 36 islands in total, only four of them inhabited: Tokashiki, Zamami, Aka and Geruma. Since 5 March 2014, most of the area has been protected as Kerama Shotō National Park.
