Check in is at 1300 and check out is at 1100. You can check in earlier than 1300 but your not guaranteed to get your site as it may not be ready. You may have to pull into the overflow and either go to lunch or catch a bus to a park. I've pulled up as early as 0630 and was directed to the overflow and once to my site. One nice thing about checking in early is you beat the long lines that form from around 1100 to 1500. Good luck.