Blue Cave

The Blue Cave is a sea cave on Xiji Islet, carved into basalt cliffs over centuries by waves and erosion. Sunlight streams through a natural opening in the ceiling, creating bright blue reflections across the water inside.

The cave took shape over many centuries as waves continuously hammered against the basalt, slowly carving out a large hollow. This patient natural process created one of the most striking features of the island group.

Local fishing families have passed down their ways of working the waters through many generations. Walking along the shores, you can observe how they continue to use the sea much as their ancestors did.

You can only reach the cave by taking an authorized boat tour departing from Magong Harbor, which runs when weather permits. Plan your visit between March and November when conditions are most favorable for boat operations.

The blue light effects are strongest when the sun reaches its highest point, creating the most vivid reflections on the water. Most visitors miss this timing and see much duller colors, not realizing when to capture the cave at its best.