Kerama Islands Snorkeling — Crystal Clear Seas of World-Class Visibility

Thirty kilometers west of Naha, the Kerama Islands — a UNESCO National Park encompassing a cluster of small islands separated by extraordinary channels of turquoise, cobalt, and emerald water — offer what marine biologists and divers have long recognized as some of the clearest, most biodiverse seas in Japan. The Kerama Blue is a specific quality of water clarity that results from the depth of the channels and the purity of the Kuroshio Current flowing through them.

Highlights

The main islands — Zamami-jima, Aka-jima, and Tokashiki-jima — each have beaches and snorkeling spots of exceptional quality. Furuzamami Beach on Zamami is consistently ranked among Japan's best beaches: fine white coral sand, water visibility exceeding 30 meters, and a reef just offshore where sea turtles graze on sea grass daily. The Aka-jima channel between the islands is a prime spot for sea turtle encounters — they are so reliably present that guides can almost guarantee sightings for snorkelers. Humpback whales migrate through the Keramas between January and March, making whale-watching tours from Zamami Port one of the most reliable humpback experiences in East Asia. Coral gardens are in healthy condition compared to many reefs worldwide.

Getting There & Tips

High-speed ferries from Naha's Tomari Port reach Zamami in 50 minutes and Tokashiki in 35 minutes (different services). Standard ferries take about 2 hours. Day trips from Naha are possible but overnight stays maximize water time. Snorkel gear is rentable on all islands. Book ferry tickets in advance for peak season (July–August).

Best Time to Visit

July–August is peak diving and snorkeling season with warmest water (28–29°C). January–March offers whale watching alongside year-round snorkeling. The sea is swimmable from April to November. Avoid typhoon weeks (peak risk: August–September).