How early did sailors go ocean-going?

What was needed for ocean-going sailships, and how early could they achieve it?

Ocean-going sailing existed very early; Greek, Chinese, and Polynesian evidence shows that capable sailors travelled far beyond short coastal passages.

Long-distance sailing began far earlier than a modern age-of-exploration narrative might imply. Ancient Greek and early Chinese evidence points to ships capable of substantial voyages. Polynesian navigation demonstrates that relatively small craft could cross enormous distances by understanding winds and currents. Coastal routes remained useful, but early ocean-going capacity was not limited to sailors hugging a nearby shore.