During the day, the Seto Inland Sea presents a tranquil appearance. At night, a fantastical blue light spreads across the sea. A small-group tour held in Tamano City , Okayama Prefecture , allows you to experience two types of bioluminescence up close: sea fireflies and bioluminescent plankton.
2026.05.29The world of bioluminescence you'll encounter in the Seto Inland Sea
Sea fireflies are small crustaceans that emit a bright blue light when stimulated.
Its luminescence is sometimes called "liquid neon," and when viewed in the dark, it looks just like stars in space.
The calm waters of the Seto Inland Sea provide an ideal habitat for sea fireflies, and places where they can be observed in high densities are limited worldwide.
A mysterious light shining in the palm of your hand
The tour involves observing sea fireflies using specially designed, environmentally friendly equipment.
The experience of seeing the glowing blue light up close in the palm of your hand becomes an unforgettable memory for many participants.
The delicate glow that can only be created by natural light is a beauty that cannot be fully conveyed in photographs or videos.
The blue sea stretches out at the water's edge.
This tour allows you to observe not only sea fireflies, but also the fantastical scenery created by bioluminescent plankton.
The coastline, which glows blue with every movement of the waves, looks like a scene from a movie.
On nights when the conditions are just right, the tranquil beaches of the Seto Inland Sea are enveloped in a blue light.
Night seminar to learn about the wonders of living creatures
A short 25-minute seminar will also be held during the experience.
A guide will provide an easy-to-understand explanation of the ecology and history of sea fireflies, as well as the mechanism behind their blue bioluminescence.
The experience becomes even more enjoyable when you not only look at it, but also understand "why it glows."
Professional photographers share their tips and tricks for taking great photos.
Trevor, who will be guiding the tour, is a professional photographer who has gained worldwide attention for his photographs of Umihotaru (a type of marine bioluminescent structure).
The book also introduces long-exposure techniques for beautifully photographing bioluminescent creatures.
Camera enthusiasts and even those participating with smartphones can capture a special moment.
A special experience that can only be enjoyed in a small group.
The tour is limited to small groups of up to 8 people.
With close proximity to the guide, each person can enjoy observing and photographing at their own pace.
Because it is conducted in a way that minimizes the environmental impact, it is also appealing because it allows you to have a valuable experience while protecting nature.
basic information
Experience details
• Meeting and Greetings: We will meet at the location, introduce ourselves briefly, and then head to the beach.
Preparation: Under the guidance of the guide, prepare the tools and bait needed to collect sea fireflies.
• Seminar: This approximately 25-minute immersive scientific explanation covers the ecology, history, and chemical reactions behind the bioluminescence of sea fireflies in the Seto Inland Sea, which are sometimes referred to as "liquid neon."
• Experiential observation: Participants will collect specially designed "devices" that have minimal environmental impact, and then have the opportunity to actually touch and observe sea fireflies.
• Environmental conservation: Our proprietary harvesting method takes maximum consideration for the ecosystem and is designed to leave no trace in the marine environment.
• Photography: We will provide instruction from a professional perspective on long-exposure photography techniques for beautifully documenting luminescence phenomena.
| item | Content |
| Venue | Okayama Prefecture Tamano City, Okayama Prefecture (around Uno Port) |
| Event period | Every year from March to November |
| Duration | Approximately 120 minutes |
| Fee | 8,000 yen per person |
| Capacity | Maximum 8 people (maximum 10 people when reserved for private use) |
Guidance team
Lead guide: Trevor
Originally from Canada, this professional photographer has lived in Japan for many years and has gained worldwide attention for his fantastical photographs of sea fireflies.
Coordinator: Simon
Originally from Australia, I am responsible for designing experiences that emphasize handcrafted, storytelling-based storytelling.
Coordinator: Matsu
Japanese. I will be responsible for customers within Japan.
Why not experience the magical night of the Seto Inland Sea?
Bioluminescent plankton glowing in the palm of your hand, and the shoreline painted blue.
Come and experience the mysteries of the Seto Inland Sea, a sight you can only find here, with your own eyes.
*You can switch languages on this site.
Contact & Media
• Email: info@setouchiguide.com
• Media Kit: - Dropbox link
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