Coral reefs across the southern Arabian Gulf have declined in the past two decades, with extensive loss of formerly Acropora table corals, which are now functionally extinct in nearshore reefs. This study documents the coral community at Sir Bu Nair (SBN), an offshore island buffered by less extreme environmental conditions, which contains the last remaining large stands of Acropora in the southern Gulf. We found that Acropora is a major reef-building coral throughout SBN. Mean coral cover was 27% (range: 6%–49%) across all sites and depths, of which more than half was comprised by Acropora. This varied around the island, with the highest densities to the south and southwest in shallow waters. Our study provides essential information for the management and conservation of these highly valuable and vulnerable corals. •Sir Bu Nair MPA conserves the last Acropora spp. reefs in the southern Arabian Gulf.•We studied coral community changes in depth, location and before and after summer.•Mean coral cover was 27% and corals belonged to 14 genera and 10 families.•We found significant differences in coral assemblages among depths and locations.•This MPA protects a unique coral community with Acropora dominated reefs.