The species inhabits deep pools of large rivers, sheltered inshore marine environments with substantial freshwater inputs, and partially isolated brackish or fresh- water lagoon or lake systems (Stacey and Leatherwood 1997, Stacey and Arnold 1999, Smith and Jefferson 2002).

During 48 sightings of Irrawaddy dolphins in Malampaya Sound, Smith et al. (in press) found significant differences between environmental characteristics in the inner and outer Sound (DF=158) for depth (F=164.54, Prob.=0.0000), salinity (F=19.27, Prob.=0.0000) and turbidity (F=21.53, Prob.=0.0000), with depth and salinity greater in the outer Sound and turbidity greater in the inner Sound, indicating the restricted environmental preferences of the Malampaya Irrawaddy dolphin subpopulation.