On this day in  history,...

...in 1565, the Spanish navigator and Augustinian friar Andrés de Urdaneta arrived in Acapulco, successfully completing the first return voyage from the Philippines to the Americas. This achievement, known as the tornaviaje, marked a turning point in transoceanic navigation and in the empirical understanding of Pacific Ocean circulation.

Urdaneta’s route was not accidental. Drawing on his experience, maritime knowledge, and access to pilot charts and accounts from Portuguese explorations, he deduced that sailing northward from the Philippines would eventually lead to favorable winds and currents. As he ascended to approximately 39°N latitude, he intercepted the Kuroshio Current, a powerful western boundary current flowing northeast along the coast of Japan, and then caught the westerlies—prevailing winds that carried his ship eastward across the vast Pacific.

Though Urdaneta had no instruments or theoretical framework to describe ocean circulation in modern terms, his voyage represents the first recorded European use of the Kuroshio Current as part of a purposeful navigation strategy. It stands as an early example of oceanographic reasoning through observation and trial, well before the formal birth of oceanography as a science.

The success of the tornaviaje opened the way for the Manila–Acapulco Galleon Trade, which would operate for over two and a half centuries, connecting Asia and the Americas in a sustained commercial and cultural exchange. It also revealed the vast asymmetry of the North Pacific circulation, where western intensification drives strong poleward currents like the Kuroshio—knowledge now fundamental to physical oceanography.

Today, Urdaneta’s 1565 crossing is not only a landmark in maritime history but also an early demonstration of how empirical oceanographic insight, even without formal theory, can shape the course of global exploration and connectivity.

Sources

•    Schurz, W. L. (1939). The Manila Galleon. E. P. Dutton & Co.
•    Spate, O. H. K. (1979). The Spanish Lake. Australian National University Press.
•    Andrés de Urdaneta y el tornaviaje. Video on youtube (in Spanish).