Onychomycosis is a common disorder that is difficult to cure. Prevalence is lower in children (0.7%), but athletes are 2.5-fold more likely to develop the disease, with infections of the toenails seven times more prevalent than those of the fingernails. This is a concern for athletes as it can interfere with their performance. The risk of developing onychomycosis is increased by the warm environment of many sports activities; the use of occlusive footwear; the warm, moist environment associated with socks and sweating; shared, close quarters among athletes; and trauma to the foot and toenail. Once infected, onychomycosis treatment requires a long duration of treatment with strict compliance, a potential problem for younger patients. Treatment carries the risk of significant side effects, and recurrence rates remain high. Avoiding infection can be a potent first line of defense and may circumvent the need for treatment. Preventive recommendations such as keeping toenails short and proper washing of laundry, to name a few, can be effective and are discussed here. Technological improvements such as synthetic, moisture-wicking socks and well-ventilated, mesh shoes have also been shown to reduce moisture and injury. Education about preventing fungal spread and improving hygiene in the locker room, gym, and pool are of critical importance. This overview of onychomycosis focuses primarily on the preventive measures and innovative changes in athletic gear. It also provides a compact step-by-step guide to prevention intended to be useful for both the general public and the professional. It can be reproduced to use as a handout for athletes, trainers, and coaches.