If another wave is crashing, take a deep breath and repeat the dive and forward push-off. Usually, waves crash in water that is shallow enough for you to touch the ground.
The worst thing you can do is run out to knee-height water and stand there as waves crash on you—knocking you backwards and using up energy. Never stand upright once past knee-height water. Keep your head down and dive forward.
The correct sequence is: Run—high knees—dolphin dives—swim straight through. Once you start running, stick to this pattern and you'll be at the first buoy in no time. Avoid a sequence of: Run—stop and turn your back on the waves--wander out a little farther until the waves come again—stop and turn your back again and get knocked toward the shore.
How Do I Get Back to Shore?
When you've made it to the home stretch, pick a spot on shore near the finish and use it to swim toward. As you reach the area where waves are forming, use their momentum to help push you forward. Instead of a slight turn to the side to breathe, turn your head a little more and peek behind you to see what's coming. If a wave is nearing, swim harder and try to gain momentum from it. Above all, stay calm.
Continue to swim once the waves are crashing. If one is about to crash on you, take a deep breath, put your hands over your head in the dolphin-diving position and bodysurf back to shore. Continue to hold your breath and maintain a streamlined position with your arms outstretched in front of you.
If you don't catch a wave, still try to use their momentum to push you forward. When you can touch the ground, begin dolphin diving. Swim until your belly is on the sand. The waves and white water will continue to push you to the shore, eliminating the need to expend energy running through the water.
The more practice you have with open water, the calmer and more confident you'll be during competition, helping to ensure a strong start to your race. Check with a local triathlon or masters swimming club to see if they have organized open water swims. Be safe and have fun.