Culhwch ac Olwen is first found in complete form in the "Red book of Hergest" (c. 1400 CE: see Other Works), though there are fragments in the "White Book of Rhydderch" (c.1325)* up to the freeing of Eiddoel*.

The most accessible translation is in the collection known since Guest* as the Mabinogion, for example, Gantz* (Penguin Classsics). The best Welsh critical edition is Bromwich and Evans*. You can find an online copy of Guest's translation* here.