Marsh frogs can reach a maximum length of 17 centimeters and, thus, are the largest frogs in Europe. The head is proportionally big, and the hind legs are long, giving them excellent jumping abilities.
There is a large variation in color and pattern, ranging from dark green to brown. Large dark dorsal spots vary considerably in size, number, and arrangement. A middorsal line is often present.
The photograph of the marsh frog was taken in the nature reserve La Petite Camargue Alsacienne recently.