When I first heard about the sport of freediving on Koh Tao, I was skeptical. In only two days, using a mask, snorkel, and fins, I could learn to hold my breath for up to three minutes, and dive down to a depth of up to 20 meters? Impossible!
But holy crap, it’s true! By the end of the course, I could hold my breath for 3:20, and had descended to a depth of 20 meters on a single breath of air!