This was an event which I had not heard of - but was on the margin of the front page of the Bangkok Post! There was even less information that I could find on the Internet BUT I found this
Event: 9th Run through the Sea to Pitak Island Event Date: 23 June 2013 Venue: At Chakgrinarubet Ship Model, Pak Nam Lang Suan, Lang Suan District, Chumphon
In June of each year, which is the month the sea level decreases in the morning so that visitors can run or walk across the sea from the coast of Ao Thong Khrok to Pitak Island. So, there have been activity of mini marathon, bike race, forest planting, open the sea for free eating, squid fishing, activities related to homestay held at Pitak Island, etc.
For more information, call TAT Chumphon Office, at 076 501 832