He was born in Lebrija. He was navigator on expeditions to the Yucatan (1506) and Brazil (1508) with Vincente Yamez Pinzón before becoming pilot-major in 1512 following the death of Amerigo Vespucci. In 1515 de Solís headed an expedition of three ships from Lepe to explore the southern part of South America for passages to the Pacific. He reached and named the Rio de la Plata in February, 1516 and sailed up river to the confluence of the Urugary and Paraná Rivers where he landed and was killed by native Charrua indians. His brother-in-law, Francisco de Torres, took charge of the ships and returned to Spain.