At the 2012 Summer Olympics in London, Sarmiento qualified for an Olympics for the second time as a crew member in the men's 470 class by finishing ninth and receiving a berth at the ISAF World Championships in Perth, Western Australia. Teaming again with Barreiros in the opening series, Sarmiento narrowly missed a chance to sail for the medal race by a single point behind the Swedes, as the Spanish duo placed eleventh in a fleet of twenty-seven boats with an accumulated net score of 104 points.