I’ll give you the cheat sheet. For 2026 (and most years): Regent Street flips on around November 7th. Oxford Street follows about a week later. Carnaby Street is usually the second week of November. Check each street’s website, because the dates shift like a moving sleigh.
But here’s a pro tip: don’t go on the switch-on night itself. It’s a human sardine can. Go two days later. The lights are still on, and you’ll actually see them without a stranger’s coat in your face.
London Christmas Lights Switch-On at Frank Hansen blog
Bonus weird fact: The switch-on button often isn’t a real button. It’s a huge, fake prop. One year, a confused mayor pressed a giant lightbulb that didn’t do anything. The real switch was under the stage. Classic London.
