This paper describes eight new species of the genus Coscinoderma from Chuuk Island, the Federated States of Micronesia. This genus is characterized by very fine, meandering uncored secondary fibres. All the new Coscinoderma species are compared with eight other valid species from tropical regions. Coscinoderma folium n. sp. is characterized by its large thickly foliate shape, and cored primary fibres are easily found between secondary fibres in choanosome. Coscinoderma lacium n. sp. differs in having round conules and no cored primary fibres. Coscinoderma cavernosa n. sp. is distinguished from other species by its cavernous shape and long sharp conules. Coscinoderma wenoa n. sp. is characterized by long conules and primary fibres. Coscinoderma mappula n. sp. differs in having a thick sand crust in the choanosome. Coscinoderma bakusi n. sp. is characterized by having several oscules at the top of the sponge and color changed grey to dark brown in alcohol. Coscinoderma pollax n. sp. is characterized by having a small thumb shape. Coscinoderma truki n. sp. similar to C. pollax in shape but differs in cored primary fibres with many spicules.