The Atlantic slave trade or transatlantic slave trade involved the transportation by slave traders of enslaved African people, mainly to the Americas. The slave trade regularly used the triangular trade route and its Middle Passage, and existed from the 16th to the 19th centuries. The vast majority of those who were enslaved and transported in the transatlantic slave trade were people from central and western Africa, who had been sold by other West Africans to Western European slave traders (with a small number being captured directly by the slave traders in coastal raids), who brought them to the Americas. The South Atlantic and Caribbean economies especially were dependent on the supply of secure labour for the production of commodity crops, making goods and clothing to sell in Europe. This was crucial to those western European countries which, in the late 17th and 18th centuries, were vying with each other to create overseas empires.
The Portuguese were the first to engage in the Atlantic slave trade in the 16th century. In 1526, they completed the first transatlantic slave voyage to Brazil, and other European countries soon followed. Shipowners regarded the slaves as cargo to be transported to the Americas as quickly and cheaply as possible, there to be sold to work on coffee, tobacco, cocoa, sugar and cotton plantations, gold and silver mines, rice fields, construction industry, cutting timber for ships, in skilled labour, and as domestic servants. The first Africans imported to the English colonies were classified as "indentured servants", like workers coming from England, and also as "apprentices for life". By the middle of the 17th century, slavery had hardened as a racial caste, with the slaves and their offspring being legally the property of their owners, and children born to slave mothers were also slaves. As property, the people were considered merchandise or units of labour, and were sold at markets with other goods and services.
The major Atlantic slave trading nations, ordered by trade volume, were: the Portuguese, the British, the French, the Spanish, and the Dutch Empires. Several had established outposts on the African coast where they purchased slaves from local African leaders. These slaves were managed by a factor who was established on or near the coast to expedite the shipping of slaves to the New World. Slaves were kept in a factory while awaiting shipment. Current estimates are that about 12 million Africans were shipped across the Atlantic,although the number purchased by the traders was considerably higher, as the passage had a high death rate. Near the beginning of the 19th century, various governments acted to ban the trade, although illegal smuggling still occurred. In the early 21st century, several governments issued apologies for the transatlantic slave trade.