The diamondback terrapin is the only turtle on the U.S. East Coast that lives in estuarine waters. The larger juveniles and adults are known to spend the summer in marsh creeks and adjacent bays, but seldom in marsh surface ponds. In the winter, they bury in the mud at the bottom of marsh creeks and open water areas adjacent to marshes.

There are only two periods in the life history of these terrapins when they live on land.