Octagonal cylindrical masonry tower attached to a 1‑story masonry keeper’s house; lantern removed. The tower and and keeper’s house are in ruins. The lighthouse was replaced by a buoy offshore. This is a critically endangered lighthouse; the building appears to be in danger of collapse. Lighthouse Digest Doomsday List. in May 2007, the Guánica municipality and the Department of Natural Resources signed an agreement to restore the lighthouse and its surroundings, but no work has begun yet. The lighthouse is within a commonwealth nature reserve, El Bosque Seco (Guánica Dry Forest). Located1.5 miles south of Guánica, where the lighthouse formerly marked the east side of the entrance to the Bahía de Guánica.
The Guanica lighthouse entered service in 1893. It was designed by José María Sainz and built on a plateau (Point Meseta) just east of the entrance to the Guanica harbor, at the time one of the best and busiest in the island. The building is 50 feet long by 28 feet wide. In contrast to most lighthouses, which followed a sober Neoclassic style, this one (like the first Rincon lighthouse) had an elaborate brick cornice and parapet. The rustic stone walls were covered with white stucco that imitates the texture of the baseboard rocks.The coat of arms of the Corps of Road Engineers was placed on top of the entrance. The octagonal tower is at the center of the building and measures 33 feet tall.
The sixth-order lens projected its light eight miles away. On July 25 1898, keeper Robustiano Rivera spotted the invading American forces and quickly traveled to Yauco to inform the Spanish authorities. The lighthouse was used briefly as a hospital during the short war. The building was transferred to the government of Puerto Rico in 1940 and the light was extinguished in 1950, since then the lighthouse has deteriorated to the point that the only remains are the exterior walls, the tower (with its iron balustrade surprisingly in excellent condition) and a very small section of the roof. The cistern and well are near the building. In May 2007, the Guanica municipality and the Department of Natural Resources signed an agreement to restore the lighthouse and its surroundings, but work has not started.