On the third day of the battle the Persian fleet was ready to attack the Allied lines in full force.
Seeing the Persian fleet assemble, the Allies attempted to block the Straits of Artemisium as best they could, and waited for the Persians to attack.
The Persians formed their ships into a semicircle and tried to enclose the Allied fleet, upon which the Allies rowed forward and joined battle.
The battle raged all day long, with the Allies hard put to defend their line.
When the fleets finally disengaged at nightfall, both sides had suffered roughly equal losses.
However, the smaller Allied fleet could scarcely afford such losses; half the Athenian ships (the largest contingent in the fleet) were damaged or lost.

 
According to Herodotus, the Athenians were the best fighters on the Allied side.
On the Achaemenid side, the best results had been achieved by the Egyptians, who wore a heavy individual equipment comparable to Greek hoplites, and were able to vanquish five Greek ships:
In that sea‑fight of all Xerxes' fighters the Egyptians bore themselves best; besides other great feats of arms that they achieved, they took five Greek ships and their crews withal.
Of the Greeks on that day the Athenians bore themselves best; and of the Athenians Clinias son of Alcibiades; he brought to the war two hundred men and a ship of his own, all at his private charges.

— Herodotus 8.17.

Returning to Artemisium, the Allies saw that they would probably not be able to hold the line for another day, such were their losses.
They thus debated whether they should withdraw from Artemisium, whilst they awaited news from Thermopylae.
Themistocles ordered the men to slaughter and barbecue the flocks of the Euboeans, so that they would not fall into Persian hands.
Abronichus arrived on the liaison ship from Thermopylae and told the Allies of the destruction of the Allied rearguard at Thermopylae.
Since holding the Straits of Artemisium now no longer held any strategic purpose, and given their losses, the Allies decided to evacuate immediately.
On the third day of the battle the Persian fleet was ready to attack the Allied lines in full force. Seeing the Persian fleet assemble, the Allies attempted to block the Straits of Artemisium as best they could, and waited for the Persians to attack. The Persians formed their ships into a semicircle and tried to enclose the Allied fleet, upon which the Allies rowed forward and joined battle. The battle raged all day long, with the Allies hard put to defend their line. When the fleets finally disengaged at nightfall, both sides had suffered roughly equal losses. However, the smaller Allied fleet could scarcely afford such losses; half the Athenian ships (the largest contingent in the fleet) were damaged or lost.
 
According to Herodotus, the Athenians were the best fighters on the Allied side. On the Achaemenid side, the best results had been achieved by the Egyptians, who wore a heavy individual equipment comparable to Greek hoplites, and were able to vanquish five Greek ships:
In that sea‑fight of all Xerxes' fighters the Egyptians bore themselves best; besides other great feats of arms that they achieved, they took five Greek ships and their crews withal. Of the Greeks on that day the Athenians bore themselves best; and of the Athenians Clinias son of Alcibiades; he brought to the war two hundred men and a ship of his own, all at his private charges.
— Herodotus 8.17.
Returning to Artemisium, the Allies saw that they would probably not be able to hold the line for another day, such were their losses. They thus debated whether they should withdraw from Artemisium, whilst they awaited news from Thermopylae. Themistocles ordered the men to slaughter and barbecue the flocks of the Euboeans, so that they would not fall into Persian hands. Abronichus arrived on the liaison ship from Thermopylae and told the Allies of the destruction of the Allied rearguard at Thermopylae. Since holding the Straits of Artemisium now no longer held any strategic purpose, and given their losses, the Allies decided to evacuate immediately.
Battle of Artemisium