The Viking Cave is located on the small Phi Phi Island south of the Great Phi Phi Island. There are several huge limestone caves on the small Phi Phi Island. The Thai government is currently only opening the Viking Cave for tourists to protect the ecological environment of the small Phi Phi Island. Visit. There are many sea Swallows in the cave, which are rich in bird's nest, so it is called "Yanchao Cave". On the nearby sea, workers may also see the hard work of collecting bird's nest.