The Türkmenbaşy International Seaport is the city's reason for existing. Ferries run across the Caspian to Baku in Azerbaijan — a crossing of roughly 12 to 15 hours in reasonable conditions — and less regularly to Astrakhan in Russia. The port handles both cargo and passengers. There is no fixed timetable; boats depart when they have enough cargo and passengers to justify the crossing, which means you may wait anywhere from a few hours to several days.
The port itself is a Soviet-era complex that has been partially modernised. The waiting area is basic. Bring food, water, and patience. The crossing is an authentic slice of Central Asian travel — fellow passengers range from long-distance truck drivers to traders moving goods between the Caspian nations to the occasional adventurer completing an overland journey.