Joe Johnston became interested in directing a Jurassic Park sequel after the 1993 original was released, and Steven Spielberg agreed he could direct a possible third film while Spielberg himself focused on other projects.

An early Spielberg-devised story had Alan Grant secretly living like Robinson Crusoe on one of InGen's islands, but Johnston felt it was implausible that the character would want to return to a dinosaur island after his first-film ordeal.

Craig Rosenberg's rejected first draft featured teenagers marooned on Isla Sorna, an aquatic Kronosaurus sequence, and a scene of characters on motorcycles evading raptors; Johnston said it read like a bad episode of Friends.

A later draft by Peter Buchman was scrapped just five weeks before filming began after Johnston and Spielberg preferred a simpler 'rescue mission' story idea pitched by David Koepp, writer of the first two films, even though $18 million had already been spent and sets had begun construction.

The film's title was almost 'Jurassic Park: Extinction' based on Buchman's draft ending where Grant refuses to leave the island, but filmmakers rejected it for implying a definitive franchise end; other rejected titles included 'Jurassic Park: Breakout' and 'The Extinction: Jurassic Park 3'.

Sam Neill turned down a role in Peter Jackson's The Lord of the Rings: The Fellowship of the Ring to reprise his role as Alan Grant in Jurassic Park III.

William H. Macy initially turned down his role due to scheduling conflicts, delaying filming by a month, until his Focus co-star Laura Dern urged him to accept the part.

Laura Dern's role as Ellie Sattler was expanded from a brief cameo into a plot-important part after she hesitated to return for just a small appearance; Spielberg suggested giving Ellie a role in rescuing the characters to convince her.

Filming began without a completed script and the ending had not even been written when principal photography started; Johnston said making the film was 'a living hell on a daily basis' and considered quitting.

William H. Macy publicly criticized the production during filming for its unfinished script, joking that someone should be fired for 'launching a $100 million ship without a rudder.'

Actors performed many of their own stunts for the plane-crash Spinosaurus attack sequence, which Macy compared to being inside a clothes dryer; stunt doubles were used for only one shot.

The full-scale Spinosaurus animatronic measured 44 feet long and weighed 13 tons, and was so powerful it accidentally ripped the head off the re-skinned Tyrannosaurus animatronic during filming of their fight scene.

The scene showing the satellite phone inside Spinosaurus feces was filmed using 250 US gallons of oatmeal.

Discoveries suggesting velociraptors had feathers led the filmmakers to add quill-like structures to the male raptors, though paleontologist Robert T. Bakker later joked they looked like 'a roadrunner's toupee.'

John Williams, busy composing A.I. Artificial Intelligence, recommended Don Davis to score Jurassic Park III, and Davis incorporated Williams's original themes alongside new ones, including a low-brass theme for the Spinosaurus.

At 92 minutes, Jurassic Park III is the shortest film in the franchise, despite having more than 400 visual effects shots—about twice as many as the previous two films combined.

For the film's home media release, Universal partnered with a company to offer 'the world's first disposable cell phone' as a promotion, but it was cancelled after the handsets—revealed to be modified Nokia phones—could not be finished on time.