Factual error: In the classroom where Jack argues with Roger next to the chalkboard we can see a poster of the periodic table of the elements. We can see some elements that wouldn't be there in 1977 since they weren't discovered until 1999.
Factual error: In the first scene in Sydney the camera pans from the opera house toward the rich North Shore suburb, except it shows that there are no houses on the shore whatsoever. In reality there are houses scattered across the shoreline.
Factual error: In the episode where Shannon is having asthma attacks, Michael get some eucalyptus plants for Sun, but the plants he gives her aren't eucalyptus.
Factual error: The location of the working dock in Sydney where Sawyer buys a gun doesn't really exist next to the Opera House, as pictured. The reality is the site has a glass cruise ship terminal, not a shabby wooden workshop.
Factual error: When Michael and Tom end their phone conversation, we hear a dial tone. But cell phones do not emit a dial tone when a call is disconnected.
Factual error: The version of Brixton underground station is very lazily reproduced: the 'U' and 'D' of the 'UNDERGROUND' roundel have been the same size as the rest of the word since before Brixton station was built; the white circle is not part of the roundel; the station appears to be accessed through a plate-glass window; there is no reason for a black cab to be parked at the side of the road; also, the cars are all parked along the right-hand side of the road, which they would never be in the UK. (00:32:10)
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. (00:04:20)
Exodus (2) - S1-E24
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'.
Factual error: When Hurley is running through 'Sydney Airport', he runs past a sign that reads 'Kamehameha', which is the name of a Hawaiian king. This sign shouldn't be there if Hurley is in Sydney Airport.
Exodus (2) - S1-E24
Factual error: In the flashback that reveals the phone call Michael makes to his mother about Walt, Walt is seen playing a Nintendo Gameboy Advance SP before the phone call. After the phone call, when Walt stands behind Michael, Walt tells Michael that he needs new batteries. However, The Gameboy Advance SP works with a rechargeable battery which cannot be replaced with common batteries.
Live Together, Die Alone, Part 1 - S2-E23
Factual error: The prison Desmond is released from looks nothing like any British prison, let alone the British military prison (the "Glasshouse"), which is more of a training camp than a traditional prison. The guards wear no cap badges on their berets (all British service personnel wear cap badges) and their berets are worn almost vertically on their heads, whereas British berets are pulled hard to the right. The NCO who releases him is credited as a "master sergeant" in the episode credits - an American rank which has never been used in the British Army. (00:05:30)
Through The Looking Glass (2) - S3-E23
Factual error: When Charlie is in the small communications room of the underwater base, after the grenade blows out the window and the water is rushing in. The water would only come up to the top of the window, anything above that would be an air pocket and water would not go any higher, yet it got completely filled over Charlie's head. (00:30:00)
Ab Aeterno - S6-E9
Factual error: Season 6, episode 9 "Ab Aeterno": The episode is supposed to take place in the Canary Islands, Spain. However all the characters speak with either Mexican, Puerto Rican, or Cuban accents. In the 19th century there wasn't such a blend of American cultures.
Factual error: Sayid puts the compass down on the map next to the magnet he was using earlier. However the magnetic field of the magnet does not interfere with the compass as it should. (00:20:55)
Factual error: Jack's scar on his left lower abdomen is reportedly from appendicitis. The appendix is on the right lower abdomen.
Factual error: The police officer introduces himself to Claire as "Officer" Barnes. In Australia, ordinary police officers hold the rank of Constable, not Officer. (00:06:10)
Factual error: This is across the whole show, but made perfectly clear in the episode "The Whole Truth" (Season 2). Korean women do not change their last names upon marriage. A woman in Korea cannot be identified by name as someone's wife. And they would never be addressed that way. But Sun's fertility doctor addresses her as "Mrs. Kwon". Korean women can adopt their husband's family name if they move to a country where that is commonplace, but Sun was still in Korea at this point, and even after they crashed on the island, she had only just left the country.
Factual error: The neurosurgeon introduces himself as "Doctor" Woodruff and also has this written on his coat. In Australia, where this scene is set, surgeons are always addressed and referred to as "Mister" after the British fashion.
Suggested correction: We call them doctors as well in Australia, not Mr.