After conquering R'yleh and the Frozen Kingdom young Howard Lovecraft must now travel to the Undersea Kingdom in order to free his captured family, protect three mysterious magical books, and prevent the impending wrath of Cthulhu.
Unfortunately the movie Howard Lovecraft & the Undersea Kingdom is not yet available on HBO Max.
| Directing | Sean Patrick O'Reilly | Director |
| Writing | Sean Patrick O'Reilly | Writer |
| Writing | Bruce Brown | Writer |
| Writing | Thomas Boatwright | Writer |
| Writing | Erik Fokkens | Writer |
| Writing | Dwight MacPherson | Writer |
| Writing | E.T. Dollman | Writer |
| Production | Michelle O'Reilly | Producer |
| Production | Sean Patrick O'Reilly | Producer |
| Visual Effects | Billy Zhao | Animation |
| Editing | Ryan Goebel | Editorial Services |
| Editing | Rob Neilson | Colorist |
| Editing | Sean Phillip Rowe | Editor |
| Sound | Andrew Osano | Orchestrator |
| Sound | Josh Plotner | Musician |
| Crew | Aaron Bartscht | Score Engineer |
| Writing | H.P. Lovecraft | Writer |
| Sound | George Streicher | Music |
| Visual Effects | Saumik Chaudhuri | Compositing Artist |
