A periplus (literally "a sailing-around' in Greek, roughly corresponding to the Latin navigatio, a "ship-voyage") in the ancient navigation of Phoenicians, Greeks, and Romans was a manuscript document that listed in order the ports and coastal landmarks, with approximate distances between, that the captain of a vessel could expect to find along a shore. Several examples of periploi have survived:

• The Periplus of Hanno the Navigator, a 6th century BCE Carthaginian colonist and explorer, described the coast of Africa from present-day Morocco deep into the Gulf of Guinea.

• The Periplus of Pseudo-Scylax, generally thought to date to the 4th or 3rd century BCE.

• The Periplus of the Erythraean Sea was written by a Romanized Alexandrian in the 1st century CE. It gives the shoreline itinerary of the Red (Erythraean) Sea, starting each time at the port of Berenice. Beyond the Red Sea, the manuscript describes the coast of India as far as the Ganges River and the east coast of Africa (called Azania).

• The Massaliote Periplus, a description of trade routes along the coasts of Atlantic Europe, possibly dating to the 6th century BCE

A periplus was also an ancient naval manoeuvre in which attacking triremes would outflank or encircle the defenders in order to attack them in the rear.