The Undersea Environment is a 1983 role-playing game supplement, written by J. Andrew Keith for Traveller, and published by Gamelords.

The Undersea Environment is a supplement that details alien oceans, including factors in the depths that affect characters such as pressure, gravity, temperature, the effects of decompression on divers, and undersea communication and combat.

[2] A companion adventure, The Drenslaar Quest was written by the same author.

[1] Watson commented that "The tight focus and elaborate detail of these supplements is both their strength and weakness.

Just about all aspects of mountain and undersea environments are covered, but I wonder just how much of this material is really going to make its way into the average adventure.