To qualify for the Boston Marathon, a runner must complete a full marathon (26.2 miles) in a qualifying time appropriate to their age and gender. Generally, men aged 18-34 must finish within 3 hours, while women in the same age group must complete it in 3 hours and 30 minutes. These qualifying times vary for different age categories, ensuring that participants are seasoned athletes ready to compete at a high level. The Boston Marathon is one of the most prestigious marathons globally, making qualification a significant achievement.