Piraeus today it is the main port of Athens, the biggest port in Greece, one of the leading ports in the Mediterranean, an important centre of the merchant marine, industry and transportation. Piraeus port is the chief exit point from the city by sea for destinations amongst the Aegean Islands and elsewhere in the east Mediterranean. Domestic destinations include all of the Aegean islands. The port in Piraeus is also used by several Europe cruise companies to welcome visitors to Greece.

The centres of Piraeus are its tree ports: the central port, the Zea Marina and Mikrolimano.