I booked the 12 Island day tour with Pioneer as something different to do during our trip and on the whole we enjoyed the day. I feel the tour should probably be worded better as it's less a tour and more an opportunity for keen swimmers and snorkelers to get out to various points in the sea and enjoy some swimming/snorkeling. If you're not swimming you can stay on the boat during the stops and just watch or relax, there is also one stop where we moored right up next to a stoney beach so if you're not wanting to go deep into the water you can get off at this stop and take a walk. Lunch was pretty good given it was included in the price with a choice of chicken or fish for everyone.
I have two major negatives to point out for this:
1. So many people seem to smoke in Turkey that if you're avoiding it due to health reasons, pregnancy or just generally this is hardly going to float your boat. Unless you get really really lucky and none of the passengers on your trip smoke, you'll always find several people on the top deck smoking constantly which really frustrated us.
2. The guys running the tour play loud music which comes out of speakers placed on the top deck and I think this is a love it or hate it thing. I personally would have preferred no music because you're really after a peaceful relaxing day on the sea but some people might enjoy it.
Due to the 2 points above, we actually resorted to sitting on the lower deck where you still get plenty of air but no smoking and the music is not as loud. For the price it costs, it's still worth doing this but you definitely get better value if you're going to be swimming, sunbathing and don't mind smokers.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.