Factual error: In the early scene where Dennis Nedry meets a man to plan the embryo theft, the subtitle says that they are in San Jose, Costa Rica. However, the sleepy coastal town in the movie within sight of the ocean bears no resemblance to the real San Jose (a cosmopolitan capital of almost 1 million people, situated 50 miles from either coast). Even the book makes this error. (00:13:10 - 00:14:45)
Factual error: Good for effect, but on the jeep when the T-Rex is chasing them and the guy looks in the driver side rearview mirror at the really, really close roar of the T-Rex, it says on the mirror "objects in mirror are closer than they appear." Actually, no driver side mirror has ever had those words on it. That is only applicable to the passenger side rearview mirror. It is due to the difference in the way those two mirrors are made.
Factual error: The way the car "slides" down the tree as Grant and Tim are climbing down is very unrealistic. Rather than hugging the trunk like it does, the branches (some of which are thick enough) would deflect it away from the trunk. (01:13:30 - 01:15:00)
Factual error: When the goat leg falls down onto the glass roof of the tour vehicle, the wound on it is much too clean. Whether it is actual meat, it looks like it was cut with a knife. Dinosaurs, like crocodiles had conical teeth and had to tear or rip their prey apart - unlike cats or dogs, whose premolars act in a scissor-like way and actually cut the meat. The wound surface should be frayed and messy. Also, a T-Rex wouldn't even be able to tear apart a goat, because it's too small to step on it and tear at it at the same time. Instead, he would chew and shake it a few times to shatter the bones, then swallow it whole.
Factual error: At the beginning of the film we are shown an amber mine in the Dominican Republic. This amber is only 45 million years old, Hammond would never bother buying the amber from there as dinosaurs disappeared from the fossil record 65 million years ago.