Chemical investigation of the marine sponge Spongia sp., collected from the Fiji Islands resulted in the isolation of three new furanoditerpenoids 1-3, along with the known compounds epispongiatriol (4) and 17,19-dihydroxyspongia-13(16),14-dien-2,3-dione (5) While 1 is a new spongian diterpene with a modified oxidation pattern, compounds 2 and 3 represent two new ring A-contracted spongians, displaying a novel and unprecedented nor-spongian carbon skeleton. Despite their labile nature the structures could be established through a combined strategy including complete analysis of spectroscopic data (NMR, MS), molecular modeling and quantum-mechanical calculations.