Travis Lytle’s review published on Letterboxd:
A Syfy Network Original Movie (sorry, wrong cable channel) that features Mayan gold, grill bedecked Coast Guard officers, and a CG dinosaur from the depths of the ocean, "Poseidon Rex" lands its every cinematic punch with a resounding thud. It is not terrible, but the limited horror adventure about treasure hunters and an awakened king of the deep does not bear a lot of weight. The story is silly, the production is thin, and the titular creature is laughably rendered. Still, there are worse uses of 76 minutes.