130,000 BC Researchers working on the island of Crete discover stone tools indicating ocean exploration capabilities of early humans dating to at least 130,000 years ago
4500 BC Around this time, cultures like those in Greece and China began diving into the sea as a source of food gathering, commerce, and possibly even warfare.
4000 BC Egyptians developed sailing vessels, which were probably used only in the eastern Mediterranean near the mouth of the Nile River.
4000 BC - 1000 AD Polynesian colonization of South Pacific Islands.
1800 BC Basic measuring of the depths is done in Egypt.
600 BC Phoenicians developed sea routes around the entire Mediterranean and into the Red Sea and the Indian Ocean. Going around Africa they reached England by sailing along the western European coast. Although they understood celestial navigation, they probably stayed within sight of land whenever possible.
500-200 BC Greeks developed trade routes in the Mediterranean using the length of the day to estimate latitude.
450 BC Herodotus publishes a map of the Mediterranean region.
325 BCPytheas, a Greek astronomer and geographer, sailed north out of the Mediterranean, reaching England and possibly even Iceland and Norway. He also developed the use of sightings on the North Star to determine latitude.
1002 Leif Erikson reaches North America 500 years before Columbus.
1405-1433 Chinese send seven voyages to extend Chinese influence and impress their neighbor states. These expensive voyages are ended after a short time. See Zheng He.
1492-1504 Christopher Columbus reaches America looking for a searoute to the Indies; discovering various lands and islands and establishing a colony on Hispaniola
1698-1700 Edmund Halley made probably the first primarily scientific voyage to study the variation of the magnetic compass, sailing as far as 52 deg S. in the Atlantic Ocean. On a previous expedition to St. Helena, he made an important contribution to knowledge of the trade winds.
1768-1780 James Cook explores the southern parts of the oceans looking for the southern continent. He was the first to use a marine chronometer to determine longitude.
1831-1836 Charles Darwin sails on the Beagle, exploring the Galapagos and many other areas. It is this work which led him to develop the concepts of natural selection and evolution.
1860 First chart of the Gulf Stream published by the U.S. Coast Survey.
1872-1876 H.M.S. Challenger travels around the world on a scientific mission taking sediment samples, water samples, soundings, and collecting many biological specimens.