Lan-yu Island is located in southeastern Taiwan with the surface area of about 45 square km in size. The inhabitants are mostly engaged in primitive farming and fishing. In October of 1979, the author visited the island and collected some land hermit-crabs which were identified to include two genera and four species. They are Birgus latro (Linne, 1758), Coenobita cavipes Stimpson, 1858, C. hilgendorfi Terao, 1913 and C. rugosus H. Milne-Edwards, 1837. Their external characteristics are described and discussed in this paper.