Which naval battle in 405 BC ended the Peloponnesian War?

The naval battle in 405 BC that ended the Peloponnesian War was the Battle of Aegospotami.

A Spartan fleet commanded by Lysander destroyed the Athenian navy near the Hellespont, the strategically vital waterway connecting the Aegean Sea to the Black Sea. Athens depended heavily on grain shipments from the Black Sea region, so losing control of the sea left the city vulnerable to starvation and siege.

Ancient accounts differ on the exact events. Xenophon says the Athenian sailors repeatedly came ashore to forage, allowing Lysander to capture their ships while they were unprepared. Diodorus describes an initial Athenian sortie followed by a wider defeat. In either version, the Athenian fleet was effectively destroyed. Athens surrendered in 404 BC, and Sparta imposed harsh terms, including the destruction of Athens’s defensive walls.

A common mix-up is Salamis, another famous Greek naval battle. Salamis was an Athenian victory over Persia in 480 BC during the Greco-Persian Wars; Aegospotami was a Spartan victory over Athens near the end of the Peloponnesian War.