Underwater Archaeological Site of Neolithic settlement has been found at Soline, a small bay located between Korcula Old Town and Lumbarda at Korcula island. In the above photo, which is a screenshot of this video, you can see underwater archeologists examining the site. Some of the found objects are now exhibited in the newly renovated Town Museum.
You can also have a look at this site – all you need is your snorkeling equipment (mask and flippers) and you can snorkel around the site. Of course, you are not allowed to touch anything. The settlement’s walls are about 4 meters below the sea surface. Here is a video: