Open House London 2026: Buildings to Visit for Free

Thirty-five years of a festival gone global

Founded in 1992 by architect and urban planner Victoria Thornton, the event originally counted just 17 events and 100 visitors, shuttled between venues by minibus. Now officially renamed Open House Festival (though the name Open House London remains the most searched and most widely used), it belongs to the global Open House Worldwide network, 60 festivals across 6 continents, with London still the founding city and largest edition, according to Wikipedia.

The 2026 programme, published on 15 July, already listed 621 venues, walks and tours at launch, including 143 brand-new additions, a figure that usually climbs past 700 as the festival approaches, according to Londontopia. The oft-repeated figure of 800 buildings, still widely quoted online, actually dates back to the 2019 edition: no official source confirms it for 2026.

To put the event’s scale in perspective: the 2025 edition, the last one for which Open City has published a full report, drew 370,541 visits, up 35% year-on-year, with 92% of visitors reporting a boost to their wellbeing, according to the official impact report.

Highlights

• Completely free access to buildings normally closed or paid-for, from government departments to architects’ homes
• Covers all 33 boroughs of Greater London, from the tourist centre to the outer neighbourhoods
• Founding member of the Open House Worldwide network, 60 similar festivals across 6 continents

Not everything in London is free, though. The Tower of London never takes part in Open House, but it offers its own early-access option, with a morning slot before the doors open to the general public.

From the Lloyd’s Building to the Zaha Hadid Archives

The Lloyd’s Building (1 Lime Street), designed by Richard Rogers in 1986, turns 40 during the 2026 edition, with access to its famous glass lifts, the first of their kind in the UK. Another first for this edition: the Zaha Hadid Foundation (Shad Thames) opens its archives to the public for the very first time, a collection of around 300,000 pieces still being catalogued, according to Time Out London.

One thing to note if you’re looking for City Hall: the Mayor of London’s office left its famous egg-shaped building near Tower Bridge in January 2022 for The Crystal, Royal Docks, where free tours are scheduled for 12 and 13 September only, according to the Mayor of London’s official statement. The BT Tower, sold in 2024 ahead of a planned hotel conversion, remains accessible in its current form: dismantling its telecoms equipment isn’t expected until around 2030. Under the Victorian-era Leadenhall Market, guided tours on 19 and 20 September give access to the remains of a 2,000-year-old Roman basilica and forum.

Another thing worth knowing: the new London Museum, in Smithfield, won’t open until 28 November 2026, after the festival closes. What the Open House programme offers in 2026 is access to the restoration site of the Poultry Market, its second phase, which itself stays closed to the public until 2028, according to the museum’s official website.

Beyond these headline sites, the 2026 programme also gives pride of place to 20th-century British architecture: the Trellick Tower, a 31-storey brutalist block designed by Ernő Goldfinger in Kensal Town, or Rogers House, architect Richard Rogers’ glass-walled home in Wimbledon. On the more classic heritage side, St Pancras Chambers with its neo-Gothic Victorian clock tower, or the Guildhall complex with its historic Livery Halls, round out a list that deliberately mixes old heritage with contemporary architecture.

Highlights

• The Lloyd’s Building marks its 40th anniversary with access to its famous glass lifts
• The Zaha Hadid Foundation opens its archives for the first time, around 300,000 pieces
• The remains of a Roman basilica and forum resurface under Leadenhall Market, 19 and 20 September only

To take in these skylines from a distance after a day of walking, an hour on the Thames between Westminster and Greenwich offers a different perspective on the view.

A two-speed booking system

The booking system runs at two different speeds, a point often glossed over by general guides. The vast majority of sites are walk-in, first come first served. 10 Downing Street is the only venue that runs a genuine ballot: registrations from 15 July to 17 August, results on 18 August, open to ages 12 and up. Other high-demand sites (BT Tower, BBC Broadcasting House, Canada House, the London Museum construction-site tour) go through standard booking, opening at midday on 19 August, and usually selling out within about twenty minutes, according to the official FAQ. A free account is required to book, with a personal itinerary tool to track your choices. The festival also relies on hundreds of volunteers, whose slots open from midday on 12 August.

The festival also shines by putting the spotlight on boroughs tourists rarely see. In Croydon, guided tours of historic pubs sit alongside the #Merky FC headquarters, founded by rapper Stormzy. In Wembley, the Punchdrunk Enrichment Stores bring a 2026 first: an immersive theatre space for young audiences. In Peckham, a walking tour traces the neighbourhood’s Caribbean heritage, while in Romford, The Round House shows off a very different side of London architecture.

If you’re extending your stay beyond the festival, Camden Town and its market remain a safe bet north of the centre, and a day trip to Bath rounds out an architecture-focused weekend nicely, with its own UNESCO-listed Georgian heritage.

Highlights

• 10 Downing Street: the only site with a genuine ballot draw, registration closes 17 August
• Croydon, Wembley, Romford, Peckham: a gateway to a London that’s far less photographed than Big Ben
• A free account is required to book, with a personal itinerary tool to track your choices