From a young age Gabriel Laiseca began sailing off the coast of northern Spain in a boat his uncle owned. Laiseca soon became a crew member in the Snipe class, sailing at local regattas and becoming world champion in the event with Juan Manuel Alonso-Allende in 1957. For the next two years Laiseca sailed in the Flying Dutchman, winning the European Championship in 1959. One year later he and Juan Manuel Alonso, the nephew of Alonso-Allende, competed in the Flying Dutchman at the 1960 Roma Olympics where they came 11th. Laiseca went on to sail in the Fastnet race, competed in the Plymouth-La Rochelle, and sailed across the Atlantic.