This is a 12 week Half-Ironman Base Training Plan for intermediate to advanced levels athletes, or beginners with a strong endurance background. This plan assumes you can run 40 minutes without issue, and builds from there. The weekly training hours are between 11 and 16. After 12 weeks of this base training, the athlete should be ready and able to begin to train more specifically for the half-ironman of their choice, meaning race-specific intensities, with the race event happening within the next 16 weeks of this plan ending. It is important that the athlete follow the intensities prescribed in this plan, in order to maximize its effectiveness.