He was born at Coruña, Galicia, the son of a renowned Basque family. His father was admiral Juan de Langara Arizmendi, who fought as lieutenant (Teniente de Navío) at the Battle of Minorca. Having entered the Spanish Navy at a young age, in 1750, as a Guardiamarina, Lángara quickly distinguished himself in various wars. From 1766 until 1771 he made several scientific expeditions, among others, three voyages to the Philippines and the Chinese seas, and made several important contributions in cartography. In 1774 he commanded the frigate "La Rosalia" on a scientific expedition, which led to several important discoveries with regards to pilotage and navigation.