The Asian Water Monitor (Varanus salvator), also known as the Common Water Monitor, is a large lizard native to South and Southwest Asia.
Water Monitors are one of the most common monitor lizards found throughout Asia, and range from Sri Lanka and India to Indochina, the Malay Peninsula, and various islands of Indonesia, living in areas close to water.
There are five subspecies of the genus Varanus salvator.

This is Varanus salvator bivittatus (the Two-striped Water Monitor) occurring on Bali, Java, Lombok, Flores and some other neighboring islands.

1st & 2nd photo: Kuta area, Bali, Indonesia, 11 October 2011
3rd photo: Nusa Dua, Bali, Indonesia, 11 October 2011