It depends on where you are and how you let. In England outside London, planning permission is not automatically required, but whole-home letting can trigger a material change of use if the property starts functioning more like visitor accommodation than a normal home. In London, you can let for up to 90 nights per year without permission. In Wales, specific use classes (C5 and C6) apply to short-term lets. In Scotland, you need a short-term let licence before taking bookings. In Northern Ireland, councils may require permission depending on the impact on the local area.