De la Fuente, who led Spain to glory at EURO 2024 before winning the World Cup in July, had a contract in place until 2028.
The new deal ensures that de la Fuente will remain in charge when Spain attempt to defend their global title on home soil. Spain will co-host the 2030 World Cup with Morocco and Portugal.
Since taking over, De la Fuente's Spain have been defeated just twice in 41 competitive matches.
Reuters have contacted the Royal Spanish Football Federation for comment.