Five new sesterterpenes (7-11) along with six known compounds (1-6) were isolated from the sponge Hyatella sp., collected off the coast of Soheuksan-do, Korea. Spectroscopic analyses revealed these compounds as scalarane sesterterpenes with oxidized furan moieties (7-10) and a corresponding lactam (11). The compounds exhibited moderate cytotoxicity, antibacterial activity, and weak inhibitory activity against isocitrate lyase.