Takamatsu Harbor Tamamo Pier Lighthouse, Maritime lighthouse in Takamatsu Harbor, Japan.

Takamatsu Harbor Tamamo Pier Lighthouse is a red cylindrical tower standing at the end of the Tamamo breakwater, distinguished by its transparent glass construction that makes it visible from across the harbor. The structure rises above the water and serves as a key navigation marker for vessels entering the port.

The structure began operations on December 28, 1964, marking an important development in post-war Japanese port infrastructure. Its construction was part of modern harbor and maritime safety improvements carried out during the country's reconstruction period.

Locals call the lighthouse Akantomodai, or "red lighthouse", and also Setoshirubi. Its nickname comes from the vermilion colour of the original 1964 west breakwater lighthouse, which the present structure replaced as a compensation facility. The glass-block tower keeps the red identity alive at night, when interior lighting makes the whole structure glow red.

The lighthouse stands at the tip of the Tamamo breakwater, about 540 m northeast of the central pier of Takamatsu Port, so it is reached on foot along the breakwater. From JR Takamatsu Station the walk takes about 15 minutes; from Kotoden Takamatsu-Chikko Station it takes about 20 minutes.

The lighthouse's exterior is made of 1,600 transparent glass blocks, each 19 cm square, set in a five-story steel frame. At night, lights inside the structure make the entire tower glow red. It was designed by the Japan Aids to Navigation Association and won a bronze prize at the 6th Spatial Design Competition in 1999.