Continuity mistake: When Jack wakes from his close encounter with Kate's sleeping pills, in the close-up his white pillow lies on the blue seat cushion, but in the next shot it lies on the grey blanket, which is spread over the cushions. (00:32:45)Super Grover
Revealing mistake: Jack's left arm is bandaged from Boone's blood transfusion. After the shot of Shannon, as she cries over Boone, Jack sits on the beach in the wideshot and the bandage is on his right arm, but in the following shots it's on his left. Yet another flipped shot. (00:41:35)Super Grover
Revealing mistake: In Season 2, Episode 18 - Dave: When Ana Lucia is threatening "Henry Gale" in the hatch cell; every time he moves and his makeshift shirt slips, you can see a line on his right upper arm where they applied make-up. Apparently he's wearing makeup on all the exposed parts of his face and neck to make him look sunburned, exposed to the elements etc. This is not just a normal suntan line, as his shirt wouldn't normally fall down that much out in the open and he's been inside for days now.
Continuity mistake: When Jack and Ana-Lucia sit in the airport lounge she takes out her cell phone when it rings, and in this shot her glass is nearly full and has plenty of ice. Yet, when she leaves a moment later, the glass is nearly empty with no ice whatsoever. (00:12:50)Super Grover
Revealing mistake: After Jack brings some survivors back to the cave, there is a shot of Hurley turning on his CD player to listen to Willie Nelson. In the next shot of Jack, as he fills bottles with water, his large tattoo is on his right upper arm, but normally it is on his left. The shot is flipped. (00:39:40)Super Grover
Continuity mistake: When Charlie walks with the crying baby on the beach, he meets Hurley and later Sawyer, and then later when Sawyer reads the "engine story" to sooth Turniphead, throughout these shots the baby's blanket constantly jumps off, on, off, etc. (00:23:40)Super Grover
Visible crew/equipment: When Boone climbs up the vines toward the plane, in the first wideshot there is a rather conspicuous round CG blur at Boone's left hip that moves as he moves. Then in some following wideshots the black stunt belt at Boone's waist is perfectly visible as he makes his way up. In Boone's close-ups no such aids are on his body. (00:30:35)Super Grover
Factual error: In the first flashback, when Charlie first hears himself on the radio, there is a close-up of the UK number-plate on the front of the van. It is the wrong colour: this is a yellow plate. As it is on the front of the van, it should be white. Only rear plates in the UK are yellow. This false plate was made up in mirror-image by the production company, as the actual van used was Left-Hand Drive. The whole scene, apart from the shot of the radio, was filmed and then flipped for the final cut, to make the van appear to be Right-Hand Drive as you'd find in the UK. Hence the moles on the right of Charlie's neck are on his left in this scene.
Factual error: Hurley arrives at the departure gate and calls to the woman to wait and let him board. As he goes through the gate, a sign with the word 'authorized' is visible to the left. This scene supposedly takes place in an Australian airport, but this is the American spelling - in Australia, the word is spelled 'authorised'.STP
Continuity mistake: When Sayid is pulled upside down in the trap, he swings toward the tree and is stabbed by the branch. It is an entirely different branch in each of the following shots: first - when he is stabbed, second - when it sticks out of his thigh, third - when he pulls it out. (00:03:20)Super Grover
Continuity mistake: When Danielle approaches the beach campsite, in his close-ups, Walt hides beside a tree and holds it with his left hand. However, in the shot between his close-ups, facing Danielle, Walt is hunched over with his hands leaning on his knees. (00:03:30)Super Grover
Continuity mistake: When Sayid is in Essam's apartment, while they are holding their glasses of tea, the positions of the glasses change between shots. For example, in one close-up the handle is under Essam's fingers, but in the next shot it's on the other side. (00:12:30)Super Grover