I've been to Skiathos four times now and have been diving with the owner, Theo, at Octopus Diving on three of these trips. If you want to go scuba diving, either as a qualified diver or for a "try dive", then this is the company I would recommend. Theo is very friendly and always conscientious when setting up the diving equipment and making sure you are comfortable in the diving equipment before getting into the water. Diving is from a small dive boat, usually a 10 - 15 minute trip out between the islands of Skiathos and Skopolos, though don't worry if you are a complete novice as there is some very shallow water around the islands. For the more experience diver there are opportunities for reef or wall dives. Usually only small groups (4 – 6people) are taken out on the boat, depending on the mix of abilities. You'll always find Theo sitting on his boat in the evening in Skiathos harbour.