Confirmed to be dedicated to the memory of series creator Stephen Hillenburg, who died on November 27, 2018 of ALS/Lou Gehrig's Disease. He receives executive producer credit in the film, as the film began development before his death.
This movie was mainly inspired by the television special to the SpongeBob series Have You Seen This Snail? (2005).
Danny Trejo recalled a moment in which he was recognized in public by a young boy, who pointed at him and kept saying "It's El Diablo!". The boy's mother was initially shocked, as she believed that he was insulting the actor. Trejo then went to the mother and clarified that El Diablo was a character that he played in the film. The mother then grabbed Trejo and told him that her son never talks.
This film marks the first time to have someone other than Tom Kenny voice SpongeBob SquarePants, but only as a child. As the same also goes for Sandy, Patrick and Squidward.
King Poseidon is voiced by Matt Berry, who previously voiced Bubbles the Magical Talking Dolphin in the previous film The SpongeBob Movie: Sponge Out of Water (2015).