Jackson Slate, famous treasure hunter, is out to find the legendary Lost Gold Of Cortez in the open waters off a secluded island in the Caribbean Sea. Using dynamite to blast his way through centuries of silt, new chasms are created reaching miles below the ancient ocean floor. From here, an ancient evil is released, that quickly, savagely, and without warning, destroys Jackson s boat and kills his crew. The sole survivor of the carnage, Jackson teams up with marine biologist, Sarah, to venture back to the site and investigate the horrific events. They extract an egg from the darkest depths of the ocean and take it back to the lab to investigate. But when it hatches, they realise they have awaken a deadly prehistoric monster, the P-Rex, which will stop at nothing until the entire island is destroyed...
Unfortunately the movie Poseidon Rex is not yet available on HBO Max.
| Directing | Mark L. Lester | Director |
| Production | Stuart Alson | Executive Producer |
| Production | Anthony Fankhauser | Producer |
| Production | Jeff Goldman | Executive Producer |
| Production | Mark L. Lester | Producer |
| Production | Felix McNulty | Executive Producer |
| Camera | Alexander Yellen | Director of Photography |
| Editing | Daniel Duncan | Editor |
| Art | John 'Skip' Weaver | Production Design |
| Costume & Make-Up | Jessica Lynn Mathis | Costume Design |
| Costume & Make-Up | Carleigh Herbert | Makeup Department Head |
| Visual Effects | Yancy Calzada | Visual Effects |
| Visual Effects | Ryan Carter | Digital Effects Producer |
| Visual Effects | Vanessa Evigan | Visual Effects Producer |
| Visual Effects | Joshua Graham | Visual Effects |
| Visual Effects | Kevin Lane | Visual Effects |
| Visual Effects | Scott Wheeler | Visual Effects Supervisor |
| Visual Effects | Howley Smoot | Visual Effects |
| Visual Effects | Christian McIntire | Visual Effects |
| Crew | Herbert Eagan | Stunt Double |
| Crew | Mike Searle | Stunt Double |
| Crew | Stephanie Tichenor | Stunt Double |
| Sound | Chris Cano | Original Music Composer |
| Writing | Rafael Jordan | Writer |
