Limnonectes shompenorum is a relatively large, robust frog. Adult females measure 72–88 mm (2.8–3.5 in) in snout–vent length.[3][4] A male measured 84 mm (3.3 in) in snout–vent length.[4]
Limnonectes shompenorum can be distinguished from its closest relatives by the following suite of characters:[3]
"(1) head narrower than body, and longer than broad; (2) interorbital distance greater than the upper eyelid width; (3) fingers with movable dermal fringe; (4) tips of fingers weakly swollen; (5) finger 4 longer than finger 2; (6) toes completely webbed; (7) dark horizontal loreal stripe; and (8) partially pigmented eggs."