The 90-day rule is the single most misunderstood piece of London short-let regulation. Every landlord who has ever considered Airbnbing their property has heard of it. Most have got it slightly wrong. The consequences of getting it wrong range from a fine to a criminal record. This piece is the plain-English version, written by an operator who runs a compliant short-let in Greater London.
What the rule actually says
In Greater London, you can let out a residential property as a short-term let for a maximum of 90 nights in any calendar year without applying for planning permission. Past 90 nights, you either need planning permission to convert the property into a short-term let (which is rarely granted for a residential unit) or you stop letting it short term for the rest of the year.
The rule comes from Section 25 of the Greater London Council (General Powers) Act 1973, as updated by the Deregulation Act 2015. It applies to the 32 London boroughs and the City of London. It does not apply anywhere else in England.
What counts as a "night"
A night counts if the property is let to a guest for one or more nights on a short-term basis. Airbnb, Booking.com, VRBO, direct bookings via your own website, and any other short-let booking channel all count. It does not matter which platform. If a guest is paying to stay for one or more nights, that is a booked night.
A night when the property is unbooked and empty does not count. A night when your long-term tenant is there does not count. A night when you or a family member are there for free does not count.
Days when a guest is checking in or checking out both count as one night each.
What counts as your "primary residence"
For the 90-day rule to apply cleanly, the property has to be your primary residence, or you have to have planning permission. If it is not your primary residence, the rule is stricter. Any short-let use is technically a change of use requiring planning permission, and 90 days is not an automatic entitlement.
In practice, most owner-occupiers who Airbnb their spare room or their whole flat while they are away are covered by the 90-day rule. Investors who own a property they do not live in are, strictly speaking, not covered by the 90-day rule and are meant to apply for planning permission before they let it short-term.
Councils enforce this in different ways. Some are strict on the primary-residence definition. Some are lenient.
How councils catch you
Councils monitor Airbnb and Booking.com listings against the electoral roll, council tax records, and their own property databases. Airbnb has been legally required to share host data with UK authorities since 2023. If your listing shows 200 booked nights on a property that is not your primary residence, the council knows.
Complaints from neighbours are the second-biggest source. A neighbour reporting a party or a suitcase in the hallway can trigger an investigation. In 2024, London councils collectively issued around 400 planning enforcement notices for short-let breaches.
The penalties are significant. First offence attracts a fine and a formal enforcement notice. Serial or wilful breaches can attract prosecution, and in a small number of cases, a criminal record.
What we do to stay compliant
Our own property in South East London runs at close to but under 90 days a year, deliberately. The remainder of the year, the calendar is either blocked out for owner use or let on a longer stay of 28 nights or more, which sits outside the short-let definition entirely.
We track the count in a simple spreadsheet, updated weekly, and cross-checked against the actual Airbnb and Booking.com booking data at the end of every month. We stop taking new short-let bookings for the current calendar year when the counter hits 85, giving us a five-night buffer for the odd late cancellation and rebooking.
Planning permission: when it is worth applying
If you own a property in London and want to let it short-let for the full year, you need planning permission for change of use to a short-term let. In practice this is granted only in specific contexts: mixed-use developments that were designed for aparthotel operation, purpose-built serviced apartment blocks, and some conversions in industrial or commercial areas that have been rezoned.
For a normal residential flat in a residential building, planning permission for full-year short-let use is almost never granted. Councils are actively pushing back against short-let conversion because of the housing pressure it creates.
If you have a property in one of the few areas where permission might be granted, an application costs around 500 to 1,500 pounds in fees plus planning consultant costs, takes 8 to 13 weeks, and has maybe a 20-30%success rate.
The proposed C5 planning use class
In 2024 the government consulted on introducing a new C5 planning use class specifically for short-term lets, which would formalise the distinction between short-let and permanent residential (C3) use. The consultation closed but no legislation has been passed. As of mid-2026 the C5 class does not exist. When or if it is introduced, it would give councils more direct tools to control short-let volumes at borough level.
Where this leaves owners considering management
If you own a property in Greater London and are weighing up short-letting it, the 90-day rule is the single biggest operational constraint you need to plan around. The maths of a well-run 90-night short-let is genuinely good, higher yield than a long-let and more flexibility on your own occupancy, but it requires disciplined booking-calendar management to stay compliant.
That is one of the things we do for owners on our management contracts. We track the day count in real time, block the calendar automatically when you approach the limit, and switch the property to longer stays for the remainder of the year if you want to keep earning outside the 90-day window. If you want to know how this would work for your specific property, our list-your-property page is the next step.