Kerama Islands Snorkeling & Diving Guide: Kerama Blue Waters Near Naha

What Is Kerama Blue — And Why the Kerama Islands Are World-Class

The Kerama Islands (慶良間諸島) sit 30–50 kilometres west of Naha, accessible by high-speed ferry in under an hour. Designated a National Park by Japan's Ministry of Environment in 2014, the archipelago protects one of the world's highest-density coral ecosystems — over 248 coral species grow in these waters, according to the Ministry of Environment.

The term "Kerama Blue" (ケラマブルー) refers to the exceptional water clarity the islands are known for. Underwater visibility regularly reaches 30–50 metres due to minimal sediment and plankton in this part of the Pacific. The clarity transforms the water into a deep, luminous turquoise that photographs unlike anything in mainland Japan — and unlike many tropical destinations, this is a measurable, consistent condition rather than a marketing claim.

For English-speaking visitors, the key advantage over other Okinawa island destinations is proximity to Naha. Unlike Ishigaki or Iriomote — which require additional flights from Okinawa's main island — the Kerama group is a direct ferry ride from Naha's Tomari Port. Among all Okinawa island destinations, the Keramas offer the strongest combination of world-class marine conditions and easy access.

Best Snorkeling Spots Across the Kerama Islands

The three main snorkeling islands — Tokashiki (渡嘉敷島), Zamami (座間味島), and Aka (阿嘉島) — each have a distinct character. Choosing between them depends on your schedule and whether you are day-tripping from Naha or staying overnight.

Tokashiki Island: Kozamami Beach and Sea Turtle Encounters

Tokashiki is the largest island in the Kerama group and is served by both high-speed and slow ferries from Naha. The prime snorkeling spot is Kozamami Beach (古座間味ビーチ) — an arc of white sand with direct reef access from shore. According to the Tokashiki Village Tourism Association, Kozamami has among the highest sea turtle encounter rates in the Kerama chain. Turtles are commonly seen in the shallows grazing on seagrass; early morning visits before tour groups arrive improve your chances considerably.

The reef drops away from the beach gradually, making Kozamami suitable for swimmers of all levels. Snorkel gear is available from rental shops at the beach. Sea turtles here are protected under national park regulations — observe at a distance and do not touch or chase them, particularly when they are resting on the bottom.

Zamami Island: Furuzamami Beach and Day-Trip Snorkeling

Zamami Island is the hub for high-speed ferry access and has the most developed tourism infrastructure in the Keramas. Furuzamami Beach is the main snorkeling spot, a short walk from the port, and the reef here delivers the full Kerama Blue effect — visibility on a clear day can extend well beyond 30 metres in either direction. The site is suitable for confident snorkelers rather than complete beginners, as the depth drops relatively quickly off the reef edge.

Zamami works particularly well for day-trippers who want to snorkel in the morning and catch an afternoon ferry back to Naha. For those wanting to go deeper into Zamami's beaches and the island's whale-watching specifics, see the Zamami Island beaches guide.

Aka Island: Nishibama Beach and Protected Reefs

Aka Island (阿嘉島) is connected to Zamami by a footbridge and shares the same high-speed ferry service. Nishibama Beach (ニシハマ) features an offshore reef designated as a protected diving area within the national park. Entry to the beach is free, but divers are required to pay a conservation fee and book through a licensed dive shop — shore snorkeling without a guided booking is permitted. The reef at Nishibama is in notably good condition because access is regulated, and sea turtle sightings from shore are common.

Diving in the Kerama Islands: From Beginners to Certified Divers

Experience Diving (体験ダイビング): No Certification Required

Experience diving (体験ダイビング, taiken daibingu) is the standard entry-level option offered by Kerama dive shops — no open-water certification is required. A certified instructor accompanies you to a shallow site, typically 5–12 metres depth, for 20–40 minutes underwater. Groups are capped at four participants per instructor, providing attentive supervision for first-time divers.

Prices from Zamami and Tokashiki operators run ¥15,000–20,000 (~$100–135) per person including equipment, briefing, and the guided dive. You should bring your own swimsuit; wetsuits and all dive gear are provided. Advance booking is essential, particularly May through October, when popular operators fill weeks ahead.

Certified Dive Sites: Ugan Drift Dive and Beyond

For certified divers, the standout site in the Kerama group is Ugan (ウーガン) off Zamami Island. According to Zamami Village Tourism, Ugan is an advanced drift dive site requiring experience with current diving — on strong current days, you drift past large schools of reef fish, sea turtles, and occasionally reef sharks. It is not recommended as a first-dive-in-Japan experience, but for experienced divers it is one of the better drift dives in Okinawa.

Beyond Ugan, the broader Kerama chain offers numerous dive sites at varying skill levels, from shallow coral gardens to deeper drift sites. Coral gardens at 10–25 metres are accessible to open-water certified divers and represent the majority of what Zamami and Tokashiki dive shops offer. Certified dive packages vary by operator; contact dive shops in Zamami or Tokashiki directly for current pricing.

Seasonal Guide: When to Visit for Snorkeling, Diving, and Whale Watching

The Kerama Islands are best visited April through October, when water temperatures reach 25–29°C and visibility is at its peak of 30–50 metres. This is the core snorkeling and diving season.

Season	Conditions	Notes
April–June	Excellent — warming water, pre-typhoon	Quieter crowds, full visibility
July–September	Peak season — warm, humid	Highest demand; book far in advance
October	Excellent — warm water, cooling air	Good balance of conditions and crowds
January–March	Cooler water, some beach restrictions	Humpback whale season; snorkeling still possible
November–December	Transitional	Fewer tours, reduced operator hours

January through March brings a different reason to visit: humpback whales migrate through the Kerama waters on their northern route. Some Zamami-based operators run morning whale-watching tours followed by afternoon snorkeling sessions. Exact availability varies by year and operator — contact dive shops on Zamami directly when planning a winter trip. Some beach areas impose temporary access restrictions in winter to protect nesting sites; confirm conditions before travelling.

For those comparing the Kerama Islands with other Okinawa snorkeling destinations, the Ishigaki Island guide covers the more distant Yaeyama chain, which involves an additional flight from Okinawa's main island but offers different terrain and conditions.

Getting to the Kerama Islands from Naha

All ferries to the Kerama Islands depart from Naha's Tomari Port (那覇港 泊港, Naha-kō Tomari-kō). From central Naha, the port is a 10-minute taxi ride or a 15-minute walk from Asahibashi Station on the Okinawa Monorail (ゆいレール, Yui Rail). Parking is available near the port at approximately ¥1,000 (~$7) per day.

Route	Type	Duration	One-way fare
Naha → Zamami	High-speed ferry	~50 min	¥4,240 (~$28)
Naha → Tokashiki	High-speed ferry	~35 min	See official site
Naha → Zamami	Slow ferry	~1.5–2 hrs	Less expensive

Ferry departures typically run between 8:00 and 17:00 depending on the route. Services cancel during typhoons and sustained strong winds — always check conditions the evening before a planned trip. The high-speed ferry can be rough in certain sea states; if you are prone to motion sickness, carrying medication is worth the precaution.

For day-trip planning from Naha to Zamami specifically — including timing and what to pack — see the Naha to Zamami day trip guide.

Practical Tips Before You Go

• Book tours before ferries: Popular dive and snorkeling operators on Zamami and Tokashiki fill their slots well ahead of high season. Confirm your tour booking before purchasing ferry tickets to avoid arriving with no available tours.
• One island per day: Inter-island ferry connections are limited, and trying to visit two Kerama islands in a single day leaves little time in the water. Pick one island and commit to it.
• Bring your own swimsuit: All dive and snorkel gear — wetsuit, fins, mask, BCD, regulator — is supplied by operators. Swimwear is not; this is consistently flagged in tour reviews.
• Sun protection in clear water: Water clarity means UV penetrates deeply. Apply reef-safe sunscreen before entering the water and consider a rash guard. Overcast days in Okinawa still deliver strong UV.
• Check cancellation terms: Tours cancel for weather and some operators offer no rescheduling. Understand the policy before booking, especially if you have fixed travel dates.
• Conservation fees at Nishibama: The protected reef zone on Aka Island requires a conservation fee (保護協力金) for diving access. The amount is small but mandatory; your dive shop will handle it as part of the booking.

Frequently Asked Questions