The Santorini volcano is worth the trip. We took a traditional caique ship on an afternoon tour. The islet has a great lava rock coastline and a clear path to the rim. There's a lot of dust and rocks, and it's a healthy grade so I'd highly suggest wearing sneakers or teva-type shoes. Also, bring water!

While staying on Santorini I took a day tour that included the Akrotiri ruins, the volcanic islets of Nea Kameni and Palea Kameni, and the island of Thirassia. Book your tour directly at a travel agency, not from your hotel. Two others from my hotel booked through the hotel, I did so at a travel agent. Each paid almost twice what I did, and their tour did not include Akrotiri. They ended up on the very same boat as me for the remainder of the tour! Akrotiri was not all that I had hoped as they were doing renovations and much of it was covered. The active volcanic islet of Nea Kameni was very cool. It is a bit of a hike to the top. I wore sturdy shoes and was glad of it, as those in flip flops had a rough time. Don't wear fancy clothes or shoes, my feet were covered in a fine black dust. Bring water. If you do these things it will be great! You can see the different colored portions of the island from the different erruptions. The big chunks of black lava rock near the base are so cool to look at! My guide was very informative and we learned a lot from her about the history of the volcanoe. She gave her spiels in several languages, english, german, and I don't remember what else. Next we stopped to swim in the warm sulphur springs off Palea Kameni, also a lot of fun. Then we went on to the island of Thirassia. You dock in the small port with several seafood restaurants for lunch. There is a larger village up top but there are many steps to reach it and time is limited, so I did not go. Instead I had lunch and then relaxed near the water. You can choose to end your tour in Fira or Oia. Be warned if you end in Oia you will be dropped off at the bottom of the cliff and will have to go up many steps to reach the town, very tiring in the heat of the day. With the hiking, swimming, and steps this tour will be most enjoyable for those that are reasonably fit. I ended the day tired but I had a great day and really enjoyed visiting the volcanic islets.

Definately take an all day boat trip that includes the volcano (you will be charged a euro to hike to the top). The hike is uphill on black rock and is hot -really hot in the summer! Take water, wear tennis shoes, not flip flops, and plan on your shoes getting dirty-not a walk for white tennies. There are little wisps of steam escaping at the summit, and the view is spectacular! You will get to experience a dip in some volcano warmed water on the other side of the island afterward, then on to Thirasia or Oia or Fira, depending on which tour you choose. Beautiful trip!