Continuity mistake: When Eggsy and Harry are walking toward the Kingsman tailors just before he gets introduced to the new weapons, there is a long shot of them walking down the street and two silver cars are coming down the street behind them. In the next shot the two silver cars that should still be in the background have disappeared. Also, as they approach the Lexus parked in front of the Tailor's, and there is no car beside them, in a second perspective, there is suddenly a black vehicle parked behind the Lexus.
Continuity mistake: When Eggsy is in the interview room at the police station, in a wide shot the tape recorder is on the table by itself, with nothing around it. Eggsy demands a phonecall, the police officer leaves, and Eggsy then reaches beside the recorder and picks up a cordless phone which has appeared from nowhere.
Continuity mistake: When Valentine is speaking with Princess Tilde through the prison door, his position changes during the reverse shots from Tilde's perspective. On his side of the door, his left shoulder is closer to the door, but in the reverse shot, his right shoulder is closer.