Character mistake: Marissa said to Ryan (in episode "The Brothers Grim") that the last time she was in Chino, she "saved his ass". She was referring to Thanksgiving, but that's not the last time she was in Chino. The last time she was in Chino was in "The Nana" when she ran there after finding out about Luke and her mother's affair.
Suggested correction: She saved his ass when she talked to Eddie about letting him stay. So her phrasing is correct.
The Distance - S2-E1
Continuity mistake: The posters on Seth's walls are different to the ones he had up when he left Newport. Since Seth has been in Portland all summer and not returned home, it's impossible for him to have changed them and extremely unlikely for Sandy or Kirsten to have either.
The Distance - S2-E1
Factual error: Julie picks up Marissa's iPod and presses the menu button, and Marissa acts as though the song has stopped, when pressing the menu button wouldn't do anything to the song - all that would do is have the playlist come up on the screen.
The Distance - S2-E1
Factual error: In the first episode of season two you see Teresa with Ryan, yet she has no bump. Season one ends at the end of the school term and season two starts off just before the school term. Therefore there's been about two and a half months of school holiday plus the time between her sleeping with Ryan and discovering she's pregnant and Ryan leaving for Chino with her - therefore she should be showing some signs of pregnancy in early season two.
Suggested correction: Not necessarily, some women, even very few, don't show until the 7th month or only put on baby weight of around 7-9 pounds.
Continuity mistake: When Ryan and Seth arrive at school Marisa goes and hugs Ryan. As she hugs him she puts her hand on his shoulders as if to hug him around the neck, or just to let Ryan hug her, but in the next shot her hands are around his waist.
The New Era - S2-E4
Plot hole: Early in the episode, Alex tells Seth that the night of the Killers concert is her night off. (She works at The Bait Shop, the concert venue.) At the end of the episode, Alex is paying The Killers, as if she were the manager on duty.
The SnO.C. - S2-E5
Continuity mistake: In Series 2, Episode 'The SnOC', we see Zach punching Seth with his right fist. However, when Summer gives him some ice, he covers his left fist with it (which is now bruised and swollen).
The Chrismukkah That Almost Wasn't - S2-E6
Continuity mistake: When Seth is holding the wheel of jobs for Chrismukkah the arrow on the wheel changes positions repeatedly in between shots.
Continuity mistake: When Ryan and Lindsay are making out, Ryan's hands change position in different camera angles, as well as the way Lindsay is sitting when Kirsten interrupts them.
Continuity mistake: While Sandy is singing and they all have their arms around each other, from the front, you see Alex is next to Zach, but from the back, Marissa is standing next to Alex and not Zach.
Continuity mistake: Sandy's hands change from being on the microphone and being in the air between shots while he's singing.
Continuity mistake: At the beginning of the episode, Kirsten and Ryan are sitting at the table. From the front you see Kirsten pick up her coffee cup. In the behind shot you see her put it down and in the next shot, which is from the front, the cup is still in her hand and she's putting it down again.
Continuity mistake: When Seth is eating alone in the restaurant, there is a plate with leftovers in front of him. In the next shot, when Zach arrives, the plate has moved to the top right side of the table.
Character mistake: Caleb tells Julie that when he had his coronary, she was in a spa in Nice, even though in the episode before it was established that Julie cancelled her trip to Nice.
Continuity mistake: In the scene where Summer is about to leave for Italy with Zach and then realizes she has forgotten Princess Sparkle, she receives a phone call from Seth. In various shots the phone is on top of her hair and under her hair.
Continuity mistake: When Summer screens the call from Seth at the airport, her phone opens without her flipping it.
Visible crew/equipment: At the beginning of the episode, where there is a shot of the poolhouse, look at the top right hand corner. You can see where the set ends.
Continuity mistake: When Sandy meets Rebbecca in the coffee shop to discuss her running away, Rebecca's coffee cup alternates from being down on the table to by her mouth, when you see her from behind, between shots.
Factual error: How exactly does Seth unlock the door? The entire purpose of locking the storeroom is to keep mall customers out so they won't steal things, not to keep people in there, so there is no way it was only lockable from the outside. If it was a key operated lock, why would someone just leave their key in the keyhole for someone to take? There is no explanation for Seth being able to unlock the door.
Continuity mistake: In season 2 episode "The Risky Business", the top Summer holds changes position in her hands.