Boat from Santorini to Oia
For approx. € 25 per person you can take a fast boat from Fira to Oia and back. You don't need to go up, but you remain down in the old port. It's well indicated. From there it's 20 minutes to Ammoudi Port in Oia. The bus from the port to the center of Oia is included and you have 1.5 hours to spend before turning back.