Guillermo Altadill is a Spanish yachtsman. In addition to the Barcelona World Race, Altadill has also competed in 18 Atlantic crossings, six circumnavigations, 300,000+ miles sailed in competition, two Volvo Ocean Race (2005/2006: Ericsson and 2001/2002: Assa Abloy), and two Whitbread Round the World Races. He also was on board the maxi-catamaran Cheyenne when it set the Jules Verne’s record for fastest tour around the world with crew.

Altadill was the Spanish Champion in Soling and Tornado and the trainer of the Tornado Gold medalist at the 1996 Summer Olympics in Atlanta.