In the Twelve Labors of Hercules, the sun god Helios lent Hercules the golden cup for crossing the ocean. Hercules used it during the journey to the far western lands, where he sought the cattle of Geryon in the tenth labor.
The cup is often described as a golden vessel or sun-cup that carried Helios across the cosmic ocean after his daily voyage through the sky. Hercules borrowed it as transportation, allowing him to travel west by sea rather than making the entire journey overland.
This episode belongs to the Geryon labor, not the quest for the Golden Apples of the Hesperides, although both adventures took Hercules to the mythical western edge of the world. Ancient accounts vary in small details, but Helios is the god traditionally associated with lending the vessel. Apollo is sometimes confused with Helios because both are linked with the sun in later popular culture, but they are distinct figures in Greek mythology.