In the beginning of the movie, when Carrie gives background information on Charlotte, she quotes her telling Harry "We're not barren, we're reproductively challenged." Charlotte actually said that to her first husband, Trey, in Sex and the City.
When Carrie reads emails from Big, they are all dated in September, when New York City observes Daylight Savings Time. The time stamp on the email incorrectly reads "EST" for Eastern Standard Time, when it should read "EDT" for Eastern Daylight Time.
When Samantha is lying on the table covered in sushi and the phone rings, she moves and the piece of sushi on her shoulder falls down. A piece of double-sided tape is visible, to hold the sushi in place. Time passes, but it's understood Samantha never leaves the table and remains covered in sushi. When the shot returns to her close up, the piece of tape has been removed from her shoulder.
When Samantha brings Carrie her breakfast in Mexico, the teapot changes from ornate to traditional, depending on the characters' points of view. The food and flower arrangement on the tray also changes; one flower becomes three depending on the cut-away.
When Carrie is leaving Charlotte's apartment and getting into the car, you can see her shoes are plain white slightly pointed shoes. However, when she is seen running at Big later on, she is wearing silver strapped up gladiator style stilettos.
When Carrie leaves Charlotte's to go to the wedding she is wearing normal white court shoes, when she is shown running towards Big to hit him she is wearing completely different shoes which are also now gold.
When Carrie makes lists to plan the wedding, the position of her Sharpie marker (clipped to her tank top) changes position several time during the shot. Just before she gets up off the bed to show her wedding dress, the Sharpie is gone.
In the scene when Carrie and Charlotte are making lists for the wedding, the Sharpie marker clipped to Carrie's tank top not only changes positions many times but just before she gets up off the bed to show her wedding dress, the Sharpie marker is gone.
After Carrie and Charlotte enter Carrie's apartment following the release of the Vogue article, Lily hands Carrie a tiny pumpkin. The first shot shows her offering it upside-down. In the next shot, the pumpkin is right-side-up in her hand.
The license plates on Big's Mercedes-Benz are obviously fake. New York State plates have three letters followed by four numbers on them. The plates on Big's car have three letters, then a mix of letters and numbers for the last four characters.
When Carrie gets her new cell phone, she complains that her new number is a different area code. Cell customers can move their numbers between phones and carriers. Carrie had changed her number to avoid contact with Mr. Big.
In the Sex and the City: The Domino Effect, Mr. Big has surgery to remove a blockage from his heart. In the bed scene, he has no scars on his chest. Heart surgery can be performed by going in through the thigh, arm or neck, especially for simple blockages or stents.
Miranda and Carrie have an argument on Valentine's Day, then don't talk for 3 days. When Miranda shows up in a taxi a few days later, it's raining, and the trees, shrubs, and grass are all green. Spring doesn't come to Manhattan that quickly.
Carrie, Samantha, Miranda and Charlotte leave Charlotte's apartment and enter the limousine to go to the wedding. When the limousine arrives at the site of the wedding and pulls up to the curb, it's clearly empty.
When Carrie reads the poets-letters to Big,she puts her glasses in her forehead to ask him if he had ever written her a love letter. In the next scene the glasses have changed position and they are on the top of her head.