There are two campgrounds that can accomodate either tents or RVs: Flamingo Campground and Long Pine Key Campground. The winter is the busy season because summers are hot, there are lots of mosquitoes, and it is also the wet season.
Long Pine Key Campground, near the Homestead entrance, is open seasonally (closed June 1 to November 14). It has 108 drive-up sites for tents and RVs. For hikers, the campground is adjacent to Long Pine Key Trail and only a few miles from the Anhinga Trail.
Flamingo Campground is on the southernmost tip of the Florida peninsula near the Visitor Center, 38 miles south of the main park entrance in Homestead. There are 234 drive-up sites with about a 1/4 of them with a view of Florida Bay.
There are also a number of backcountry camping sites which are open to visitors with a backcountry permit from one of the visitor centers or the main park entrance. Most locations are accessible by boat, canoe or kayak with a few reachable to hikers near Flamingo or Everglades City. The majority of backcountry camping sites are in the vicinity of Ten Thousand Islands and the surrounding rivers.
East Cape Sable: The southernmost point on the mainland of the United States is an undeveloped five mile beach within Everglades National Park. Camping is available there with a backcountry camping permit. It is accessible by boat, 11 miles west from the Flamingo Visitor Center.