This half Ironman plan covers many weeks of challenging, but attainable training for someone who has some endurance experience, and ideally some Olympic distance races within the past season.
A half iron distance race is defined as:
1.2mile Swim | 56mile Bike | 13.1mile Run
1,930meter Swim | 90km Bike | 21k Run
Start this program if you can consistently swim 40min, run 60min and bike 90min.