Mulroy Bay is a sheltered inlet on the Donegal coast that offers reliable diving even when conditions on the open Atlantic make other sites impractical. The site list includes Horn Head and Melmore Head for advanced divers seeking walls, drop-offs, and cave systems down to thirty metres, alongside gentler shallow reefs at Portnablagh and Marble Hill suited to beginners. Kelp forests run through many of the sites, and species recorded in the area include gorgonians, pollack, wrasse, tompot blenny, and spiny lobster. Water is cold for most of the year, reaching its warmest in mid to late summer.
Monthly water temperature across Mulroy Bay's sites, from satellite sea-surface data corrected for depth. The band shows the site-to-site spread.
Temperatures are among the lower end for Irish coastal diving, staying cold from autumn well into late spring and peaking only briefly in summer. The sheltered nature of the bay means that sites like Portnablagh and Marble Hill can be dived when exposed headland sites at Horn Head or Melmore Head are ruled out by swell or strong currents.
2 operators
Water temperature around Mulroy Bay ranges from about 9°C in January to 15°C in July, based on satellite sea-temperature data for its dive sites.
In the warm season (about 15°C) a 7mm or semi-dry suit is comfortable in Mulroy Bay; in the coldest months (about 9°C) step up to a drysuit.
Fin maps 5 sites in Mulroy Bay (3 scuba diving sites and 2 snorkelling spots).
4 more sites to explore
