Board a high-speed boat at Naha's Tomari Port and within 35 minutes, the ocean transforms before your eyes. The deep navy of the open sea gradually lightens until, as the islands draw near, layers of emerald and cobalt merge into an impossible gradient. This is Kerama Blue. Designated as Japan's 31st National Park in 2014, the Kerama Islands (慶良間諸島) are Naha's nearest paradise and the sea that "the world has fallen in love with" (世界が恋する海).
The Secret of Kerama Blue — 50-Meter Visibility Powered by Coral
"Kerama Blue" is more than a tourism slogan. It describes a real color produced by water clarity reaching 50 to 60 meters — among the world's highest. The secret lies in the Kuroshio Current, one of the planet's strongest warm currents, which continuously feeds crystal-clear deep-ocean water into the area. Meanwhile, 248 species of reef-building corals (approximately 62% of all species found in Japan) act as natural filtration systems.
Registered as a Ramsar Convention wetland in 2005 (353 hectares), the Kerama waters were designated as Japan's 31st National Park on March 5, 2014 — a date deliberately chosen as "Coral Day" (サンゴの日, 3/5). The protected area expanded dramatically to 8,290 hectares. Kerama's corals also serve as a larval supply source for the reefs along Okinawa's main island western coast, making this an ecologically critical marine zone.
Getting to Kerama from Naha — Complete Ferry & High-Speed Boat Guide
The gateway to the Kerama Islands is Naha's Tomari Port (泊港/Tomarin). Two separate ferry routes operate to different island groups, each run by a different operator.
To Tokashiki Island (Tokashiki Village): The Ferry Tokashiki takes 70 minutes one-way at 1,690 yen, while the Marine Liner Tokashiki high-speed boat takes just 35 minutes at 2,530 yen. The standard schedule is the 9:00 AM high-speed boat out and 4:00 PM (summer) or 3:30 PM (winter) return.
To Zamami & Aka Islands (Zamami Village): The Ferry Zamami takes 120 minutes at 2,150 yen, while the Queen Zamami high-speed boat takes approximately 50 minutes at 3,200 yen. The Queen Zamami stops at Aka Island en route, so it's about 50 minutes to Aka and 70 minutes to Zamami.
Booking tips: Zamami web reservations open 55 days before departure; Tokashiki opens 1 month before. Peak seasons (July-August and Golden Week) sell out fast — book on the opening day. An environmental cooperation tax of 100 yen one-way (200 yen round-trip for Zamami) applies separately.
Tokashiki Island — Swim with Sea Turtles on Kerama's Largest Island
Tokashiki (渡嘉敷島) is the largest island in the Kerama group at 15.8 km², stretching roughly 9 km north to south with about 740 residents. At just 32 km from Naha, it's the closest major island and the most popular choice for day trips.
Two signature beaches await. Aharen Beach (阿波連ビーチ) is an 800-meter stretch of white sand ranked 6th in Japan on TripAdvisor's Travelers' Choice awards. The uninhabited island of Hanari-jima sits just offshore, accessible by boat.
Tokashiku Beach (渡嘉志久ビーチ) is nicknamed "Turtle Beach" for good reason — 4 to 5 green sea turtles live here year-round, rising to the shallows to feed on seagrass. Time your visit right and you can swim alongside them with near certainty. The crescent-shaped bay is calm and family-friendly.
Zamami Island — A Michelin 2-Star Beach and the Island of Whales
Zamami (座間味島) covers just 6.7 km² with approximately 580 residents, yet it's the tourism hub of the Kerama Islands. The star attraction is Furuzamami Beach (古座間味ビーチ) — a crescent of white sand stretching approximately 1 km that earned two stars in the Michelin Green Guide. Walk a few steps into the water and you're surrounded by coral reefs and tropical fish — no tour needed, just bring your snorkel gear.
Ama Beach (阿真ビーチ) fronts a wooded campground and offers calm, shallow waters ideal for families. At high tide, your chances of encountering sea turtles are high. The adjacent campground features bungalows and BBQ facilities.
Zamami also carries heavy historical weight. On March 26, 1945, US forces made their first landing in the Battle of Okinawa right here in the Kerama Islands — at Aka Island at 8:04 AM, Geruma at 8:25, and Zamami at 9:00, six days before the main Okinawa landing on April 1. Peace memorials stand on the islands today.
Aka Island — Kerama Deer, a Natural Monument, and Okinawa's Finest Beach
Aka Island (阿嘉島) is the smallest of the three main inhabited islands with just 264 residents, yet its Nishibama Beach (ニシ浜/北浜) is considered the most beautiful in the Kerama group. The name "Nishi" doesn't mean "west" in standard Japanese — in Okinawan dialect, it means "north." This 700-meter to 1-km white sand beach ranked 9th in Japan on TripAdvisor.
Aka Island has a unique resident: the Kerama Deer (ケラマジカ, Cervus nippon keramae) — a subspecies of Japanese sika deer that's smaller than its mainland counterpart, distinguished by heart-shaped white markings. Designated a National Natural Monument in 1972 when Okinawa reverted to Japan, these deer can be spotted casually wandering through villages and across beaches.
The Aka Bridge (阿嘉大橋, 530 meters, completed 1998) connects to Geruma Island (population ~60), and the bridge itself is a viewpoint where you can spot sea turtles in the waters below. Aka Island also houses the Sango Yuntaku-kan National Park visitor center, where you can learn about the coral ecosystem.
Encountering Humpback Whales — A 98% Chance, January to March Only
Every year from January through March, humpback whales (ザトウクジラ) that have fattened up in the waters of Russia and Alaska migrate to the Kerama Islands for breeding and calving in the warm seas. These massive creatures — 12 to 14 meters long and weighing 30 to 40 tons — make Kerama their winter home. Approximately 300 whales are confirmed each season, and the Okinawa Churashima Foundation has photo-identified over 2,000 individual whales by their tail flukes.
The Zamami Village Whale Watching Association, established in 1991, has over 30 years of experience. Tour prices are 7,700 yen for adults and 3,850 yen for children. The key to their success is a spotter system: observers stationed at Inazaki Observatory (elevation 118m) scan the sea with binoculars and radio coordinates to tour boats in real time. This system delivers an encounter rate of approximately 98%.
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Day Trip Itineraries & Practical Booking Guide
Tokashiki day trip: 8:30 AM arrive at Tomari Port → 9:00 high-speed boat departure → 9:35 arrive Tokashiki → village bus to Aharen or Tokashiku Beach → 10:30-3:00 PM beach, snorkeling, and lunch → 4:00 PM (summer) or 3:30 PM (winter) return boat → arrive Naha.
Zamami day trip: 8:30 AM Tomari Port → 9:00 Queen Zamami departure → 9:50 arrive Zamami → rent a bicycle or walk to Furuzamami Beach → 10:30-4:00 PM snorkeling, beach, island exploring, lunch → 5:20 PM last high-speed boat → 6:10 PM arrive Naha.
Budget guide: Ferry round-trip ranges from 3,210 yen (Tokashiki ferry) to 6,080 yen (Zamami high-speed). Snorkeling tours with equipment run 8,700 to 10,700 yen. Island restaurant lunch: 800-1,500 yen. Total budget: approximately 5,000 to 15,000 yen (transport + activities + meals) covers a full day.
What to bring: Swimsuit, towel, water-friendly shoes, reef-safe sunscreen (to protect coral), seasickness medicine (essential for high-speed boats), sunglasses, hat, cash (some island shops are cash-only), and a waterproof phone case. The best season is late June to early July — right after the rainy season ends but before peak crowds. October to November also offers fewer visitors and stable weather.
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