In the book, the megalodons are pure white -- almost luminescent -- from living in an environment with virtually no light. This coloring proved too difficult to render in CGI while still looking realistic, so the megalodons were colored like great white sharks instead.
Eli Roth was attached as director before being replaced by Jon Turteltaub. Roth left due to creative differences with the studio, namely that he wanted the film to maintain both its R-rating and a $150 million budget. It was also rumored that Roth, on top of writing and directing, also wanted to play the lead role of Jonas, but the studio believed he did not have the star power.
The film is based on the book "MEG: A Novel of Deep Terror," the first book that author Steve Alten ever published.
At one point, Jason Statham's character, Jonas, jumps into the water and starts singing to himself, "Just keep swimming, just keep swimming..." This is an homage to the character Dory in Finding Nemo (2003), which the song comes from.
The film was initially set up at Disney in 1997 when the book was published, a bid which cost the studio nearly one million dollars. The project eventually went into turnaround after Disney caught cold feet about competing with Warner's 1999 killer shark pic Deep Blue Sea (1999). Alten, frustrated at the lack of movement on the project, wrote his own draft which he showed to Nick Nunziata, who then in turn delivered to Guillermo del Toro. Del Toro took the project to Lawrence Gordon and Lloyd Levin, who brought on Lara Croft Tomb Raider: The Cradle of Life (2003) director Jan De Bont to helm.
In the book, the Meg only attacked at night since living in the deep water made its eye sensitive to light. It only attacked in daylight when it had been blinded during the course of the book. The movie, however, had the Meg in daylight with no consequence.
Just before the Meg attacks Suyin in the plastic shark cage, you can hear a fast paced version of the cello theme music from Jaws (1975).
Jason Statham is actually an expert swimmer in real life and represented England in the 1990 Commonwealth games diving category (although he failed to win). Footage of him competing can be found online. Therefore a lot of the shots of him in the water are real and a stunt double was only used for the more hazardous stunts.
The name of the Yorkie in this movie is Pippin. The lab in Jaws (1975) was named Pippit.
In its early stages of development, the film was touted as a George Clooney vehicle.
The Meg (2018) marked the return of noted film producer Gerald R. Molen to Hollywood filmmaking.
The name of the boat at the end of the film is "Charlotte." This is also the name of the ship that the character Benjamin Franklin Gates searches for in National Treasure (2004), which was also directed by Jon Turteltaub.
When Disney Hollywood Pictures first bought the rights to the novel in 1996, they hired Tom Wheeler, television writer and producer to write a screenplay for the movie. However, his script wasn't considered to be very good so Disney hired another screenwriter Jeffrey Boam, who was most well known for writing scripts for films like Indiana Jones and The Last Crusade (1989), The Lost Boys (1987), Innerspace (1987), Lethal Weapon 2 (1989) and Lethal Weapon 3 (1992), but his screenplay was also rejected for same reasons as Wheeler's. When New Line Cinema took over the project in 2005, another script was written by Shane Salerno, writer of both Alien Vs Predator films, and Jan de Bont was involved in it as director and Guillermo Del Toro as producer, but ultimately it was cancelled once again.
Another reference to a Jaws film (this time Jaws: The Revenge), during the scene with the many beachgoers towards the end of the film, there is a quick shot of a few people on a "banana" boat. In Jaws: The Revenge, this same style boat is used in one of the few deaths in the movie.
The film is loosely based on the 1997 novel "Meg: A Novel of Deep Terror" by Steve Alten.
Actresses Li Bingbing and Ruby Rose both appeared in films from the "Resident Evil" franchise. Li appeared in Resident Evil: Retribution (2012) and Rose appeared in Resident Evil: The Final Chapter (2016).