Don't look back at the land.

Not to be overly sarcastic, but don't look back. Seriously, you'd have to stop, turn around, and stick your head way up out of the water to see back anyways, and if you did this, you'd really piss off other swimmers. Also, don't stand on the shore before the start and gaze off into the distance in awe and say, "Wow, that's a big swim course." The swim course is unique in that it is the only part of the tri where you can (for the most part) see the entire course from one vantage point (ie, the shore). As such, even a few hundred meters looks duanting.

As others are sure to say, you need to practice in open water, preferably with someone else swimming right next to you, occassionally making contact with you and you making contact with them. It is the physical contact that spooks most people, followed by the lack of visibility.

If you really have a phobia of open water, why are you doing tris? If you aren't sure how to cope with it, whichever strategy you take needs to be hammered out before race day. Fear of open water should be treated no differently than inexperience or apprehension in group riding: no one wants to ride with you because you are a danger to others. Don't let race day be the first time you've been in an open-water situation. If not for your own safety, then for safety of others. No one wants a paniced swimmer right next to them.

+1. I'm a weak swimmer; the wetsuit gives me a lot of confidence & lets me focus on just swimming.

What are you panicing about? Are you a weak swimmer? Do you think you'll just panic due to the sheer number of people swimming around you?

What's your phobia about?

Either way, get some practice in open water, just as overcome mentioned, stay close to the side and swim parallel to the shore so you can just stand up if you freak out.

Have had the same problem. I just get very "internal" and focus on stroke. Keep my mind on how my hand should feel as it's sweeping back, counting strokes until my next peek-forward, etc., etc. In other words, I tune-out the "big-picture" that I'm swimmimng out in the Atlantic several hundred yards from shore and just get super-focused on the mechanics of swimming. Next thing you know, you're there.

+1 on "getting internal." My mind would freak out and all I could think about was getting OUT of the water. I love to swim, but being in the open water was just "different" to me. I went to races to study what the distances looked like out of the pool. A swimmer friend of mine told me to sing a song or count strokes- do anything to keep my mind from wandering to the dark place, where I would freak. Me being the "Buckupnorth" chose the Ohio State fight song and sang it over and over in my head, just to keep focused or "not focused" on swimming. It worked:) Now my mind can even wander a little and the panic attacks are gone. Sounds weird, but it really worked for me and got me even more hooked on tri. Good luck- I feel your pain.