Seven new lobane diterpenoids, namely, lobocatalens A–G (1–7), were isolated from the Xisha soft coral Lobophytum catalai. Their structures, including their absolute configurations, were elucidated via spectroscopic analysis, comparison with the literature data, QM-MNR, and TDDFT-ECD calculations. Among them, lobocatalen A (1) is a new lobane diterpenoid with an unusual ether linkage between C-14 and C-18. In addition, compound 7 showed moderate anti-inflammatory activity in the zebrafish models and cytotoxic activity against the K562 human cancer cell line.