This GPS enabled watch has just about everything a triathlete could want. Offering advanced run, cycle and swim functions, it's compatible with your iPhone/iPad so you can track your progress in training and analyze it after. Paired with the Suunto Smart Sensor, which is the smallest Bluetooth Smart compatible heart rate sensor available, you can keep tabs on your heart rate metrics swimming, biking, and running. If you have a smaller wrist, check out the women's-specific Ambit3 Sport Sapphire watch, which comes with smaller sizing.