Koch became interested in traditional Hawaiian spirituality in the early 1990s, but soon became interested in another feature of the islands: the sand. He brought his skis, tried skiing on the sand, and found that it offered a surprisingly fast surface. In the past, Koch had skied through gravel pits and over pine-needle-covered forest floor, so skiing on sand was no surprise to him. He noticed that sand, like snow, varied according to the season, location, and weather conditions. He had been interested in sand skiing since the early 1980s, but could never find any really fast sand that was conducive to his workouts.
In 1997, Koch moved to Hawaii so he could sand-ski year-round, and created a Web site, www.sandskiing.com, about the sport.
In an article in USA Today, Koch told Sharon Raboin that when he skis on Hawaiian beaches, the sunbathers "almost can't believe their eyes. One in 10 are amazed enough to get off their towel and take your picture. I never complete a workout without being stopped a couple of times." Koch doesn't mind, since he wants to publicize this new twist on the sport; his mission is to get more people out on cross-country skis, and if the sport can move to sand, so much the better.
Koch told Raboin that sand skiing had one notable feature: "This won't work with just any sand. It must be coarse, yet firm." He explained to Bigford, "Finding the right sand is kind of elusive. Like snow, it changes every day, seasonally and according to conditions." But when the sand is good, he told Raboin, "This is the best way to train."
U.S. biathlon manager told Lyle Nelson told Raboin, "When Bill says this [sand skiing] is better, you can't discount it. He's the most creative person I've ever met. He always comes at things at a different angle. That's why he was world champion in a sport that's not popular in the U.S."
In recent years, Koch has become concerned about the use of illegal, performance-enhancing drugs by athletes. "It seems that everybody is convinced that drugs are very, very important to winning," he told Bergin. "This is a false notion that has to be dispelled." He said that although he knew that other athletes were using banned substances during the years he was competing, he decided that competing with them would simply be a greater challenge, and he was able to beat them. Koch also noted that young skiers "need to be guided to focus on learning how to tap into their own personal powers, which always have more potential than any drug."
Koch told Raboin that he believes more people should try cross-country skiing: "I love the sport so much. I truly believe it's a therapeutic, healing endeavor. I believe if more people cross-country skied, the world would be a better place." And, he told Bergin, "I certainly plan to ski all the days of the rest of my life."