The British steam tanker San Tiburcio was a 5995 ton vessel  that sank in the Moray Firth due to the explosive effect of a mine during the early stages of World War 2. The loss was on the 4 May 1940 when the vessel broke into two pieces aft of the central bridge and sank in her present position. The wreck lies upright on a fairly flat silty bottom.

She served in the petroleum trade and ran between ports in the Gulf of Mexico and the UK The ship had been converted to fit a stern mounted 3 inch gun for its war service.

The mine had been laid three months earlier by a German Submarine which had slipped through the waters unseen, laying  contact mines at a depth of  8 metres; enough to allow small coastal vessels to pass over them safely. There was little point wasting a valuable mine on a small fishing boat when it was intended for much bigger prey. For three months the mines had lain in wait for an unsuspecting victim.

The Captain at the time was Walter Frederick Fynn and he and the whole crew of 40 were saved. He later went on to Captain the San Arcadio, which was torpedoed and sunk by a German U-Boat on 31 Jan, 1942 where he lost his life.

Various items from the wreck are displayed in "The Captains Table" café, which is part of the Findhorn Boatyard at Findhorn.

The wreck has become an artificial reef providing safe refuge and food for countless fish. She has become a very popular diving site with charter boats operating  from Nairn, Cromarty and Balintore.