No re-entry. I asked the same question last year, but I then realized leaving would take too much time. The place is like a state fair. I brought my digital camera in with no problems, but I arrived at 7pm. My advice, bring a disposable. Bayfront park is a city park, so no sand, but when night falls, the skyscapers come alive. Don't bring a back pack, they won't let you in with it. Wear shorts with big pockets. Ultra is a lot of work, but a lot of fun. Good Luck, Smith Point