Competitors dressed as a mermaid and King Neptune happily plunged into the murky waters as they prepared to swim the length of the 120-yard course.
Since it was first held in 1986 to raise funds for a new community centre in the Welsh town of Llanwrtyd Wells, the championship has attracted global media attention.
So popular is the event that in 2012 the town decided to hold its first World Alternative Games, bringing together a two-week programme ranging from worm charming and gravy wrestling, to snail racing and beer mat tossing.
More than 2,000 people took part in 35 events that year, and it continues to draw crowds from around the world.
Yesterday’s programme included husband dragging, wife carrying and the ditch race – but the highlight of the games undoubtedly remains the bog snorkelling, which took place at Waen Rhydd bog.
The Games come to an end tomorrow with the single boat tug of war and quadrathlon, before a closing ceremony.