Sanxiantai is a geological rock that turned out to be a headland. Gradual erosion cut the neck that connected the mainland to the main island, and thus became offshore islands. Tourists who used to visit this place could only reach the island during low tide. In 1987, the government completed the eight cross-sea arch bridge that crosses over to the island. It was designed in the shape of waves, like a prostrate sea dragon and connects Sanxiantai with Taiwan Island. It has become the most famous landmark on the East Coast.
The entire Sanxiantai area is about 22 hectares with the highest point about 77 meters above sea level. There is a trail that goes around the island, it takes about 2 hours to go around it with no rush. Coral reefs surround the island, because of the strong weathering and erosion that made up the legendary stories about the natural landscape, such as Xian-Jian Gap He-huan holes and Sanxiantai, there are also some natural wonders around, such as the scattered sea trenches, sea caves, sea columns, sea walls to surprise tourists who visit the island.