The labourers, identified as Raju Sonakanth Kadwa (30) and Kashinath Kathodi (55) were desilting a nullah on Ghodbunder road, drowned as they could not gauge the depth, senior police inspector Kapurbawdi police station J D Kadam said.
The bodies have been sent to Thane civil hospital for postmortem, they said.
Both the labourers were engaged by a private contractor to clean aorund 20 nullahs here.