The Kerama Islands (Kerama Shoto National Park), 35–40km west of Naha, Okinawa, contain some of the clearest, most biologically diverse marine waters in Japan — often called Kerama Blue for the extraordinary visibility (30–40m on good days) and vivid color of the water. The three main inhabited islands (Zamami, Aka, Tokashiki) are reachable by high-speed ferry from Naha (35–70 minutes) and offer world-class snorkeling, diving, and sea kayaking without the development of the main Okinawa island.
Snorkeling
The Kerama Islands’ reef systems are among Japan’s healthiest — 250+ coral species, hawksbill sea turtles (exceptionally habituated to human presence on Zamami and Aka), reef sharks, manta rays (seasonal), and dense tropical fish populations. The best snorkeling sites: Nishibama Beach (Aka Island) — calm, clear, turtles virtually guaranteed; Furuzamami Beach (Zamami Island) — larger beach with coral immediately accessible from shore; Aharen Beach (Tokashiki Island) — the most accessible from Naha ferry. Glass-bottomed kayaks are available at all main beaches. No-boat snorkeling from beach entry is the dominant approach; guided tours reach more remote reef patches. Water temperature: 22–29°C year-round; wetsuit recommended November–April.
Sea Kayaking
The calm, island-dotted waters between the Kerama islands are ideal sea kayaking territory — transparent water, minimal tidal current, frequent turtle encounters, and views of uninhabited islands reachable only by paddler. Operators on Zamami and Aka offer: half-day tours (¥6,000–8,000, includes equipment, guide, snorkeling stop); full-day island-hopping (¥12,000–15,000); multi-day camping trips to uninhabited islands. The Zamami–Aka island crossing (2km) is a classic short paddle with turtles almost guaranteed in the channel between islands.
Diving
The Kerama Islands have numerous certified dive shops on each island. Notable sites: Ama Beach Wall (Zamami, coral wall drop-off); Kuba Dive Site (strong current site with schooling fish); Manta Scramble equivalent sites near Aka (manta rays, spring season). Most operators require PADI or equivalent certification; discover scuba programs available for beginners. The humpback whale season (January–March) brings mothers and calves into Kerama waters — whale watching boats and occasional dive encounters are an extraordinary bonus.
- The high-speed Queen Zamami ferry from Naha Tomari Port reaches Zamami in 50 minutes (¥3,140 one-way); Tokashiki is 35 minutes (¥2,530).
- Book accommodation 3–6 months ahead for Golden Week (late April–early May) and Obon (mid-August) — the islands have very limited capacity.
- The Kerama deer (Kerama-jika), a subspecies endemic to the islands, are frequently seen at dusk on Zamami and Aka.