Blue Cave

Well knownIn most guidebooks for this region — but rarely with the practical detail.

Researched and written by Hinato

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Okinawa · Onna

26.5558°N, 127.8072°E

Blue Cave looks different depending on the season, the weather, and the time of day — none of which a single photo can tell you.

The Blue Cave (青の洞窟, Ao no Dokutsu) is a partially submerged sea cave near Maeda Point where sunlight filtering through the underwater entrance reflects off the white sandy bottom, creating an electric blue glow that illuminates the entire cave interior. The phenomenon is most intense midday (11:00–14:00) when sunlight enters at the optimal angle.

The cave is Okinawa's most popular dive and snorkel site — accessed via a boat ride from Maeda Port or a 15-minute swim from shore (for confident swimmers). Inside the cave, tropical fish swarm in the blue-lit water, and visibility often exceeds 20 meters.

Before you go

Access hours

Last return ~4:00 PM)

Closed: Tours cancelled in rough weather or low visibility conditions

Entry fee

Guided tour: ¥4,000–6,000/person (includes equipment, wetsuit, guide, photos) | DIY equipment rental: ¥3,000

Best time to visit

Year-round | Midday (11:00 AM–2:00 PM) for peak blue glow intensity | Off-season for smaller crowds

Time to allow

2–3 hours (guided tour including boat transport)

Making the trip

Directions

Maeda Point, Onna Village. A drive from Naha or a drive from Naha Airport. Guided snorkel tour: ¥4,000–6,000/person (2 hours, includes equipment, wetsuit, guide, boat transport, photos). Shore entry DIY possible but challenging (rental equipment ¥3,000). Book tours 1 day ahead.

What to bring

**Tour vs DIY:** Guided tours dominate the Blue Cave (20+ operators), providing boat transport, equipment, safety guidance, and underwater photography (usually included). DIY shore entry is possible but requires strong swimming (200-meter swim to cave, currents can be tricky), equipment rental from Maeda dive shops, and confidence in open water. First-timers: book a tour. Experienced snorkelers: DIY saves ¥3,000 and avoids crowds. **Avoiding crowds:** The Blue Cave sees 100+ visitors daily in peak season (July–August), with 5–10 groups inside simultaneously. Early morning tours (first departure 8:00) encounter fewer groups. Alternatively, visit off-season (November–March) when water temperature drops to 22°C (wetsuit required) but the cave is nearly private. The blue glow intensity is identical year-round. **Visibility factors:** The blue glow requires three conditions: (1) sunlight (overcast days mute the effect significantly), (2) calm water (waves stir up sediment reducing clarity), and (3) midday sun angle (optimal 11:00–14:00). Check weather forecast and sea conditions before booking — operators cancel trips in bad conditions but only refund if they cancel, not if you cancel due to weather.

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