Varanus nuchalis belongs to the subgenus Soterosaurus, which was derscribed by ZIEGLER & BÖHME (1997). The Spiny-neck Water Monitor can reach a total length of up to 130 cm.
The coloration is dark black, the pattern is variable. While specimen from the islands of Negros, Panay and Cebu show indifferent cross bands of light spots on the back, animals from the islands of Masbate and Ticao show no pattern on the back and are uniformly black. In all animals of this species, a distinct white pattern is visibel on the head. The scales on the neck are elongated.
This species is also adapted to water, which can be seen on the laterally compressed tail. The length is about 1.4 - 1.7 times the SVL.