Continuity mistake: When Tim and Lex first arrive, Lex is wearing a purple tank top with a colorful design, and in the following scenes or even between consecutive shots her tank top changes to completely different designs, though it's the same style of tank top.
Continuity mistake: After the T. Rex rolls Explorer 4 upside-down with Lex and Tim inside, in the closeup when the dinosaur bites on the rubber tire we see the hub hole at the center of the wheel rim, but two shots later the wheel cover is back on the wheel.
Continuity mistake: While Lex and Tim are hiding in the kitchen, when the large serving spoon falls it cuts to the closeup of the two Velociraptors and the tall shelving unit has vanished, but in the next shot when the one of the raptors leaps onto the counter that tall shelving unit is back.
Continuity mistake: After Gennaro runs off to hide in the restroom there's a shot of the fence cables ripping apart, and in the following shot of the back of one of the Explorers note that it's missing its black roof vent (and rear wiper), but in following shots of Explorers 4 and 5 the vents are intact on both vehicles. Then just as the T. Rex starts pushing Explorer 4 upside-down its roof vent is gone (presumably, the vehicle missing the vent is a stunt vehicle).
Other mistake: When Dr Grant and the children reach the perimeter fence, Dr Grant tries to see if he can fit through, to no avail. When he and the kids start to climb, however, it is quite obvious that both Tim and Lex would have been able to crawl through quite easily, and that only Dr Grant should have had to climb over. Partly this links to the mistake here, where the holes in the fence are much bigger in the first shot, then when he tries to widen them he's holding a different part of the fence where they're smaller.
Continuity mistake: When both Explorer vehicles are parked at the paddock, in the shot of the goat being raised to lure the T. Rex, the "No! Feeding..." sign is permanently affixed to the front of the concrete wall, but in the previous and following shots that same sign is affixed to the angled top part of the wall. Later, when the power goes out, that sign is once again affixed to the front of the concrete wall.
Continuity mistake: When Grant grabs onto the electric fence, his hands are a short distance apart and there is a set of vertically positioned wiring in between his hands - the warning sign is also barely covering the "hole" in the wires. A couple of shots later, without letting go of the fence, his hands are much further apart and there are now three sets of vertically positioned wiring in between his hands. The angle of the wires also changes, and the sign is now well into the "hole", very near his hand.
Deliberate mistake: When the raptor breaks into the control room and is hopping around the computer workstations, we see sharp, distinct genetic coding projected from a computer screen and across the raptor's face (starting 1:55:50). Aside from the fact that computer displays have never projected focused images onto nearby surfaces, the projected text shown in this scene oddly reads from left-to-right, when it should actually be a flipped mirror-image (right-to-left). Spielberg probably realised this factual incongruity while filming but chose to use the left-to-right text for the sake of audience recognition, given that the multiple lines of "GATC" genetic code were already confusing enough. (01:55:50)
Continuity mistake: While they're in Explorer 5, when Ian shows Ellie an example of "unpredictability" her watch reads 5:00, then when Ellie examines the Triceratops' tongue her watch has sped forward and reads approximately 6:05, and a moment later when Dr. Harding hands Ellie the flashlight her watch has run backwards, and now reads approx 5:40. (00:50:40)
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.
Continuity mistake: When the tyrannosaurus is crushing the upside down Landcruiser and mud begins to flow in through the side shattered windows, Lex and Tim are already completely muddy all the way from the tops of their heads, possibly from previous takes.
Continuity mistake: When Muldoon and Hammond are talking about the tropical storm the first time we see a shot of Nedry's workstation behind them and there's hardly anything on the floor, but a few minutes later when Hammond says their lives are in Nedry's hands suddenly the floor is covered in trash.
Continuity mistake: Right after the "Objects in mirror are closer than they appear" shot, the dinosaur breaks a huge trunk that falls forward. A shot later note behind the dinosaur and the huge trunk is nowhere to be seen.
Continuity mistake: When the five characters start to leave the helicopter upon arrival on the island, Richard Attenborough is not sitting opposite Jeff Goldblum as he was moments earlier as the helicopter descended to the pad.
Suggested correction: Perhaps he just wanted to exit the helicopter first, so he switched places when the helicopter had touched down. You can see they had already undone their seatbelts, so they had time to move around before the door opened.
Revealing mistake: Wile driving away from the dinosaur Malcolm tells the driver to go fast. The stunt driver is very noticeable - he has a bigger head and way more hair than the actor.
Other mistake: While being chased by a T-Rex, after it breaks a trunk the digital dinosaur runs behind the car. There's a couple of shots of the people in the moving car and the next time we see the dinosaur angle the background clip is the very same one used before.
Continuity mistake: When the T-Rex escapes, the lawyer leaves the door open. Next scene, the door is closed. Then open, then closed again. Then open for Timmy to close it. Also, when the T-Rex escapes, he walks away between the trucks. The tail is already passed them. Then the girl turns the spotlight on, and the T-Rex is back to where it started. Hasn't crossed between yet.
Continuity mistake: Tim finds the goggles and puts them on. He climbs into the back seat and Lex watches him. The scene cuts to outside the car and Lex is looking forward.
Continuity mistake: The two cars are stuck in front of the T-Rex enclosure and after the lawyer got out and ran away and left the kids in it, the driver's door is open, then shut in two other shots and then back to open.
Continuity mistake: When Tim is looking at the night goggles, Lexi says something to him. She continues to look at him for a second. Then in the next shot she suddenly has her back to him.