Four species of Laboulbeniales collected from Java Island, Indonesia between August and September in 2006 are described. These species, which belong to the genus Coreomyces and were found on the family Corixidae of the order Hemiptera, were as follows; Coreomycus corixae Thaxter, Coreomyces micronectae Thaxter and Coreomyces orientalis Thaxter, which were found on Micronecta sedula Horvath, and Coreomyces recurvatus Thaxter, which was found on Micronecta sedula Horvath and Xenocorixa sp. C. corixae Thaxter and C. orientalis Thaxter were originally found on Micronecta, whereas C. recurvatus Thaxter was originally found on Xenocorixa. All species described herein are new to Java Island. The specimens were deposited in the Biological Herbarium, Division of Science Education, College of Education, Chosun University.