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O Iso Lighthouse

Fl White 3s🇯🇵Suo-Oshima, JPOperational

Location & Light Range

About O Iso Lighthouse

Constructed in 1937, this cylindrical concrete tower stands 16 meters tall and is painted white. Originally, the structure featured red and black horizontal bands, but it was repainted entirely white in 1986. The lighthouse emits a white flash every three seconds, visible for 11.6 nautical miles. It is situated on a dangerous rock in the narrow channel between Yashiro Shima and the mainland, approximately 2.5 km west of the Oshima Bridge. The focal height of the light is 14 meters.

Why it matters: This lighthouse is indispensable for safe passage through the narrow channel between Yashiro Shima and the mainland, specifically warning mariners away from the dangerous rock it occupies. Its active white flash helps prevent groundings in a critical shipping lane near the Oshima Bridge.

Light & Optic

Characteristic Signature
Fl White 3s
Flash Type
Flashing
Light Color
White
Interval
3s
Raw Code
Fl W 3s
Focal Height
14m
Geographic Range
11.6NM

Construction & History

Year Built
1937

Significant events: repainted all white in 1986 from original red and black horizontal bands

References & Identifiers

Nearest Port
Kasasa, Yamaguchi(0.6 km)
ARLHS No.
JPN-1647

Tower & Structure

Tower Height
16m
Tower Shape
cylindrical
Tower Color
white
Material
concrete

Structure: round concrete tower with lantern and gallery, painted white

Location

City
Suo-Oshima
Country
🇯🇵Japan
Region
Yamaguchi Prefecture
Sea Region
dangerous rock in the narrow channel between Yashiro Shima and the mainland, about 2.5 km west of the Oshima Bridge
Latitude
33.9541°
Longitude
132.1773°

Nearby Vessels

Flag
Type
Name
Dist.
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Frequently Asked Questions

How do mariners identify O Iso Lighthouse at night?+
O Iso displays the characteristic Fl White 3s. Each lighthouse has a unique flash pattern published in the List of Lights, allowing mariners to positively identify it and distinguish it from other navigation aids in the area. The white color may indicate a specific sector or warning zone.
Which ports and harbors does O Iso Lighthouse guide vessels into?+
O Iso Lighthouse assists vessels approaching 5 nearby ports. The closest is Hirao at 2.2 NM to the W. Other ports served include Yanai (2.4 NM W), Kuka (4.1 NM E), Tsuzu Yamaguchi (5.9 NM N), Hikari (12.3 NM W). Mariners should consult the relevant chart for full approach and pilotage information.
Is O Iso Lighthouse still active and maintained?+
Yes, O Iso Lighthouse is currently operational. It is actively maintained and continues to emit its characteristic light signal for marine navigation. Most modern lighthouses are automated and monitored remotely by the national maritime authority.
What shipping routes pass near O Iso Lighthouse?+
O Iso Lighthouse is located within the Japan / Korea shipping lane — a busy shipping corridor linking the major ports of Japan and South Korea. This makes it an important navigation reference for commercial shipping traffic in the region.
How can I track vessels near O Iso Lighthouse?+
You can track vessels near O Iso Lighthouse in real time using MarineRadar. The platform shows live AIS positions of ships in the area, including vessel name, type, flag, speed, and course. Use the "Track Vessels Nearby" button on this page to open the live map centered on this lighthouse.