Leviathans
Leviathans are massive sea monsters in Subnautica 2. These gigantic creatures tend to be hostile, and some even guard major objectives that you'll have to swim to during the main story. This IGN guide compiles a list of every Leviathan we've found in Subnautica 2's Early Access period.
Collector Leviathan
The Collector Leviathan is a massive squid-like beast that patrols the chasm between the first and second regions in Subnautica 2. This thing is big enough to destroy a Tadpole submarine with just a few attacks. If you're unlucky enough to get caught outside of a Tadpole, it'll kill you instantly.
The Collector Leviathan uses sonic pulses to detect prey, so it can track you down even without a direct line of sight. Avoidance is the best strategy when dealing with a Collector Leviathan.
If the Collector Leviathan spots you, toss a Distraction Flare to get its attention. If you're in a Tadpole, it's better to just stay inside to avoid an instant kill. The Tadpole can take a few hits, and its speed is more than enough to help you reach safety on either side of the chasm.
Great Jaw
The Great Jaw is a huge clam Leviathan that can be found in the shallow starting region of Subnautica 2. Since it's a clam, this Leviathan doesn't swim around.
The Great Jaw is located next to the Cicada Wreck (Canteen), which is 300 meters south of the Lifepod at a depth of 50 meters.
