Diamondback water snakes are one of the larger medium sized snakes in the Escambia area. They range in length from 48 to 63 inches and may be quite heavy bodied as adults. The dorsal ground color is green, olive, brownish, or grayish.
The term diamondback is misleading as the diamond shaped markings down the back or actually reticulated pattern. There are rather small (compared to other snake species) blotches found on the middle of the back and large bars that extend up from the ventral line. There are often small lines that connect the blotches to the bars. All of these markings are brown or grayish. Larger adults may be a solid brown or olive when they are dry.

The tail is ringed and the rings are the same color as the dorsal markings. The belly is entirely yellow or cream anteriorly changing to yellow with brown half-moon shaped markings. These markings may be sparse or absent in the center and become much more numerous at the edges of the belly. The labial are bright yellow. Newborn diamondback water snakes look like light versions of the adults.

The preferred habitat is marsh and swampy areas, moist woods with abundant leaf litter cover.

While the Diamondback Water Snake bite is nonvenomous, it is known to be quite aggressive when caring for its young, in which both male and female appear to take part.