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Ashika Shima Lighthouse

Fl White 3s🇯🇵Yokosuka, JPOperational

Location & Light Range

About Ashika Shima Lighthouse

Also known as: Ashika Shima (Sea Lion Island)

Ashika Shima lighthouse, operational since 1916, stands on a dangerous rock approximately 1.5 kilometers southeast of Kurihama harbor. This cylindrical concrete tower, built in 1916, measures 14 meters in height and emits a white flash every 3 seconds from a focal height of 16 meters. Its construction material is concrete and its exterior is painted black with a white lantern. The lighthouse guides vessels with a geographic range of 12.2 nautical miles. It is located near Yokosuka in the Kanagawa Prefecture of Japan.

Why it matters: This lighthouse warns vessels of a hazardous rock formation, which is particularly important for ships navigating into or out of Kurihama harbor. Its distinctive black tower with a white lantern also serves as a landmark for local mariners.

Light & Optic

Characteristic Signature
Fl White 3s
Flash Type
Flashing
Light Color
White
Interval
3s
Raw Code
Fl W 3s
Focal Height
16m
Light Range
11NM (20.4 km)
Geographic Range
12.2NM

Construction & History

Year Built
1916

References & Identifiers

Nearest Port
Kurihama(0.8 km)
Admiralty No.
M6355
ARLHS No.
JPN028
Wikidata
Q126487767 →

Tower & Structure

Tower Height
14m
Tower Shape
cylindrical
Tower Color
black with a white lantern
Material
concrete

Structure: broadly conical and tapered round concrete (?) tower with lantern and gallery

Location

City
Yokosuka
Country
🇯🇵Japan
Region
Kanagawa Prefecture
Sea Region
dangerous rock about 1.5 km southeast of Kurihama harbor
Latitude
35.2121°
Longitude
139.7351°

Nearby Vessels

Flag
Type
Name
Dist.
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Frequently Asked Questions

How far offshore can Ashika Shima Lighthouse be seen?+
With a focal height of 16 meters and a nominal range of 11 nautical miles (approximately 20.4 km), Ashika Shima is visible from well offshore under standard atmospheric conditions. Actual visibility depends on observer height, weather, and sea state. This range makes it a significant coastal navigation aid for vessels transiting the area.
How do mariners identify Ashika Shima Lighthouse at night?+
Ashika Shima 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 Ashika Shima Lighthouse guide vessels into?+
Ashika Shima Lighthouse assists vessels approaching 5 nearby ports. The closest is Kurihama at 1 NM to the NW. Other ports served include Hamakanaya (1.6 NM NW), Uraga (1.8 NM NNW), Maguchi (5 NM SW), Yokosuka (5.3 NM NNW). Mariners should consult the relevant chart for full approach and pilotage information.
Is Ashika Shima Lighthouse still active and maintained?+
Yes, Ashika Shima 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 Ashika Shima Lighthouse?+
Ashika Shima 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 Ashika Shima Lighthouse?+
You can track vessels near Ashika Shima 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.