I could tell you to do some post-race stretches, but I’d be a hypocrite. I usually grab my medal, hit the food spread and then collapse into a chair. If you think you are in contention for an age-group or category award, you may want to hang around to see if you’ve placed. The top three finishers from each category will have the honor of stepping up onto the podium and reap the rewards of their hard work. This is a great opportunity for a photo op from your race Sherpa.
After recovering for a bit and cheering on the people crossing the finish line after you, go to the pre-designated area to pick up your bike and your T1 and T2 bags containing your swim and bike gear. If you did a full Ironman distance, it’s possible but unlikely that your special needs bags will be available for pickup as well.
When leaving the race site, you may be famished, or you may feel nauseous and not craving food at all. Regardless, try to eat a full meal within two hours of completing the race. You need, and deserve, to eat to replace the calories you’ve burned. Now is also a great time for those glasses of wine or beer which you eschewed the night before.