Largetooth sawfish
Adults are primarily found in estuaries and marine waters to a depth of , but mostly less than . Nevertheless, the species does appear to have a greater affinity for freshwater habitats than the smalltooth sawfish ("P. pectinata"), green sawfish ("P. zijsron"), and dwarf sawfish ("P. clavata"). Largetooth sawfish from the population in Lake Nicaragua appear to spend most, if not all, of their life in freshwater, but tagging surveys indicate that at least some do move between this lake and the sea. Captive studies show that this euryhaline species can thrive long-term in both salt and freshwater, regardless of its age, and that an acclimation from salt to freshwater is faster than the opposite. In captivity they are known to be agile (even swimming backwards), have an unusual ability to "climb" with the use of the pectoral fins and they can jump far out of the water; a individual jumped to a height of . It has been suggested that this may be adaptions for traversing medium-sized waterfalls and rapids when moving upriver. They are generally found in areas with a bottom consisting of sand, mud or silt. The preferred water temperature is between , and or colder is lethal.
Largetooth sawfish
The largetooth sawfish can be found worldwide in tropical and subtropical coastal regions, but it also enters freshwater and has been recorded in rivers as far as from the sea. Historically, its East Atlantic range was from Mauritania to Angola. There are old reports (last in the late 1950s or shortly after) from the Mediterranean and these have typically been regarded as vagrants, but a review of records strongly suggests that this sea had a breeding population. Its West Atlantic range was from Uruguay to the Caribbean and the Gulf of Mexico. Although there are claimed reports from several Gulf Coast states in the United States, a review indicates that only those from Texas are genuine. Other specimens, notably several claimed to be from Florida, were likely imported from other countries. Its East Pacific range was from Peru to Mazatlán in Mexico. Historically it was widespread in the Indo-Pacific, ranging from South Africa to the Horn of Africa, India, Southeast Asia and Northern Australia. Its total distribution covered almost , more than any other species of sawfish, but it has disappeared from much of its historical range.