In the continued search for novel bioactive substances from the Taiwanese octocoral Briareum excavatum collected at Orchid Island, three new briarane-type diterpenoids, briacavatolides D–F (1–3) were isolated from the acetone extract. The structures of these compounds were elucidated by extensive NMR spectroscopic analysis and physical data. The anti-HCMV (human cytomegalovirus) activity of 1–3 and their cytotoxicity against selected cancer cell lines were evaluated