Eannes worked in Prince Henry's household. On Eannes' first trip down the coast of Africa in 1433, he only sailed as far as the Canary Islands. In 1434, Eannes rounded Cape Bojador, and then landed on the coastal desert. He found no people there, only a few hardy plants, including "Saint Mary's roses," which he brought back to Portugal as proof of his accomplishment.

Eannes made another journey in 1435, again rounding Cape Bojador and sailing south; he sailed with Alfonso Goncalves Baldaya. About 50 leagues past the cape, they entered a large bay and saw a caravan of men and camels. Eannes named the river Rio de Ouro. Baldaya sailed farther south and collected thousands of seal skins; this was the first commercial cargo brought to Europe from that part of Africa.