Which explorer was the first to establish a sea route to Asia?

The first European explorer to reach Asia by sea was Vasco da Gama, a Portuguese captain who arrived on the coast of India in 1498, six years after Christopher Columbus believed he had landed in Asia. Da Gama was one of a series of explorers who sought to reach Asia by sailing around the Cape of Good Hope on the southern tip of Africa. His voyage marked the beginning of Portugal's attempts to profit from the enormous trade opportunities that existed on the Indian subcontinent, particularly in the city of Calicut. Through violence and rather forceful diplomacy that essentially discarded centuries-old traditions governing maritime and overland exchange in Asia, they established footholds along the coast of India, gaining control of the spice trade in particular. Later Portuguese voyages would carry would-be European traders into Southeast Asia, China, and modern Indonesia, thus marking a major development in the establishment of global trading networks.
http://southasia.ucla.edu/

https://www.biography.com/explorer/vasco-da-gama