Not the first, but real Atlantic sailors
The title makes a claim that does not hold up. The Phoenicians were not the first people to sail the oceans. Long before the first Phoenician ships left the Levant, people had crossed substantial stretches of open sea elsewhere. The settlement of the islands of the Pacific by ancestors of Polynesian peoples, which began thousands of years ago, involved voyages of enormous length; the story of Pacific settlement and the skills of Polynesian wayfinding are a far more impressive example of open-ocean seafaring. Closer to the Phoenicians, Egyptian crews had sailed down the Red Sea on the Punt expeditions, and Bronze Age sailors crossed the open Aegean and eastern Mediterranean.
What is well supported is narrower. The documented Atlantic voyages of Phoenician and Punic sailors show that they were among the earliest known Mediterranean peoples to establish regular routes through the Strait of Gibraltar and along the Atlantic coasts of Iberia and northwest Africa. This article sets out what the evidence shows, and where it gives way to legend.
Gadir and the Atlantic coast of Spain
The key site is Gadir, modern Cádiz, just outside the strait on the Atlantic side. Ancient writers placed its foundation around 1100 BCE, but the archaeological evidence so far points to the 9th or 8th century BCE for the earliest firm remains. A temple of Melqart, whom the Greeks identified with Herakles, was famous there, and the “Pillars of Herakles” were associated with the strait.
Phoenician objects and settlements are known elsewhere along the southern Spanish coast and up into Portugal. Southern Spain was the source of silver and other metals, and the local kingdom or culture usually linked with it by Greek writers is called Tartessos. The ties between the Phoenician traders and the people of this region are a matter of active study, and they appear to have involved exchange and cooperation as well as colonial settlement.
Morocco and the offshore islands
Further south, Phoenician and Punic material has been found on the Atlantic coast of Morocco. Lixus, near modern Larache, is traditionally linked with early Phoenician presence, though the earliest archaeological layers are debated. The small island of Mogador, at modern Essaouira, had a trading station from around the 7th century BCE onward, with Phoenician-style pottery. The existence of these places suggests regular voyages along the African coast, probably in search of metals, ivory and other goods, and of fishing grounds. Local peoples, such as the ancestors of the Mauri of Mauretania, were part of these exchanges.
The Carthaginian voyages: Hanno and Himilco
Some of the best-known accounts concern Carthage, a Phoenician colony that became a power in its own right, so they speak for the western Phoenician world and not for the homeland cities. A Greek text called the Periplus of Hanno describes a voyage down the Atlantic coast of Africa, probably in the 5th century BCE, with colonists being settled on the way. How far it went is debated: the text describes a volcano, a gulf, and hairy “wild people” whom the text calls Gorillai, and scholars have proposed places ranging from Senegal or Sierra Leone to Cameroon. The surviving text is a Greek version, and its reliability is argued.
An account of a voyage by Himilco northward from Gadir survives only in a much later Latin poem from the 4th century CE, which quotes older material. It describes a hostile, foggy sea full of seaweed. Many scholars treat the details as unreliable, and it is unclear how far Himilco really went.
The story of circling Africa
The most famous Phoenician legend is told by Herodotus. He writes that the Egyptian king Necho II, around 600 BCE, sent Phoenicians from the Red Sea to sail around Africa and return through the Pillars of Herakles, a voyage that took three years, with crews stopping to plant and harvest grain. He adds that the sailors said that, sailing west around the southern tip, they had the Sun on their right, and that Herodotus himself did not believe it.
That last detail is actually the source of the argument. In the southern hemisphere, a ship sailing west would see the midday Sun to the north, on its right side. Some scholars think it is an authentic detail that a storyteller would be unlikely to invent. Others point out that Herodotus is writing about 150 years after the supposed event, that no other source confirms it, and that the story could have been shaped by the retelling. The verdict is open. It is possible, but unproven, and in any case it would not support any claim that the Phoenicians were the first to sail the open ocean.
Claims that go too far
Over the years, various claims have been made that Phoenicians reached the Canary Islands, the British Isles (for tin), or even the Americas. The most famous American claim is an inscription said to have been found in Brazil in the 19th century, which scholars generally regard as a forgery. There is no accepted evidence of Phoenician crossings of the Atlantic. Tin from Cornwall is sometimes linked to them, but the evidence for Phoenician sailors reaching Britain is weak; the better-documented northern voyage is that of the Greek explorer Pytheas of Massalia, whose Pytheas voyage took place in the 4th century BCE.
What this adds up to
The real achievement of the Phoenicians in the Atlantic was to turn a few hazardous voyages into regular trade through the Strait of Gibraltar and along the coast of Spain, Portugal and Morocco. They were skilled coastal and open-water navigators in the Mediterranean sense, but they were not unique, and the more spectacular stories rest on late, indirect or doubtful sources. Careful readers will do best to separate the evidence from the legends added later.