Phoenician merchants
The earliest explorers are barely remembered legends. Among legendary voyages is that of Jason and the Argonauts, now thought to record the first Greek expedition into the Black Sea, probably about 1000 BCE. Unknown Phoenician merchants opened up the western Mediterranean around the same time, establishing a farthest outpost at Gadir (Cadiz, Spain) on the Atlantic not far beyond
the Pillars of Hercules (Strait of Gibraltar).
Circumnavigating Africa
According to Herodotus, Pharaoh Necho sent an expedition from the Red Sea around 600 BCE that circumnavigated Africa clockwise over a period of three years. Few believe this, although Necho’s ships probably did travel far down the east coast of Africa. Herodotus also tells of an early Persian expedition intended to circle Africa counterclockwise sometime between 485 and 464 BCE. These explorers traveled some way down the west coast of Africa before turning back.

Carthage in Control of Gibraltar
About the same time as the second African expedition recorded by Herodotus, there was a Carthaginian effort to set up colonies, described by its commander, King Hanno. From his descriptions of the places encountered, it is apparent that he reached at least what is now Sierra Leone on the west coast of Africa, but perhaps traveled as far as Cameroon. The Carthaginian colonies he founded on the Atlantic coast were much farther north, however, along the shores of what are now Morocco and Western Sahara. Partly because of their Atlantic colonies, the Carthaginians controlled the Strait of Gibraltar for over a hundred years, making it almost impossible for any further exploration of the Atlantic by others from the Mediterranean regions.
Greatest recorded voyage of exploration of ancient times
But one daring sailor made it past the strait, probably about 310 BCE. From there Pytheas of Marseilles completed the greatest recorded voyage of exploration of ancient times, circumnavigating Great Britain and reaching Norway (or possibly Iceland). Not only did Pytheas travel about as far as Columbus did during his first voyage, but he returned with careful reports on all he had seen and with excellent navigational data. The primary purpose of the trip was probably to locate the source of tin, which he found in Cornwall, but Pytheas had scientific goals in mind as well. Yet few at the time believed his accounts of frozen seas and other wonders.
Explorers along the coast of western Asia
Explorers also traveled along the coast of western Asia, but their names have been lost. These routes were pioneered by Indian and Arab navigators perhaps as early as 3000 BCE. The traders that followed the explorers eventually were displaced by Egyptians under the Ptolemies, starting with two voyages to India around 120 BCE by the explorer Eudoxus of Cyzicus.
Trade between Rome and the East
By the reign of the Roman Emperor Augustus (27 BCE to 14 CE), there was regular trade between Rome and India, with hundreds of ships setting out from the Red Sea each year, many of them reaching India’s Malabar coast and returning. Gradually the shipping routes were extended, with the farthest known extension being a trip (recorded by the Chinese) of a merchant to Vietnam in 226 CE. Chinese vessels then took the merchant to their emperor in Nanking. Travel went the other way as well. Chinese expeditions had traveled to Mesopotamian outposts of the Roman Empire as early as 97 CE.

The Polynesians
Among the most amazing early explorers were the Polynesians. Their lack of a written language prevents our knowing the names of the men and women who pushed into the edge of the South Pacific as early as 32,000 BCE and settled most of it between 200 BCE and 1000 CE. Finding the tiny, remote islands of the Pacific was an amazing feat.

The Chinese explorers
The Chinese also explored many islands, but their islands were larger and closer together –– Japan, Taiwan, the Philippines. There is little evidence to support the most amazing claim of the Chinese, however. According to a legend dating from at least the sixth century CE, a Chinese junk captained by Xi and He around 2640 BCE sailed east from Japan for thousands of miles and found a continent. If true, it could only have been one of the Americas. One account has them traveling via the Bering Sea and penetrating as far south as Guatemala, while others have them reaching the Pacific Northwest and the coast of Ecuador. The best proof that something of this nature could occur are well-authenticated accounts of Japanese boats blown off course and landing in the Americas in the late 18th and early 19th centuries.