The Thames Barrier

How the Thames Barrier works, and when it is scheduled to close.

The Thames Barrier is one of the largest movable flood barriers in the world. The Environment Agency runs and maintains the Thames Barrier as well as London’s other flood defences.

You can follow us on Twitter @AlanBarrierEA or read our blog posts. or like our Facebook page

Photograph of the Thames Barrier

The Thames Barrier

Forthcoming scheduled closures

The Environment Agency operates the Thames Barrier every month for maintenance and testing, in addition to the annual test at a high spring tide.

The gates may begin closing and re-opening up to an hour before the times listed below:

  • Sunday 4 October 2020 9:05am to 7:05pm

Annual full tide test closure

The annual test closure is a unique chance to come and see the Barrier and Gates in operation. During the test, the flood gates will rotate into the fully closed defence position to stop the high tide going upstream into London.

Very occasionally, the Environment Agency may need to change or cancel a closure at short notice. Please call the Thames Barrier to check: 020 8305 4188.

Due to COVID 19 there will be no public event for this year’s annual closure, and unfortunately the café and Information Centre will remain closed.

However, visitors can still come to the site and park for free in our car parks. They will be able to walk down to the riverfront to view the Barrier in action. The closure takes place between 9:05am to 7:05pm.

The toilets and disabled lift will remain open.

Key times to view and see the Barrier in action are:

Gates begin to close at 09:30am All gates closed by 11:25am Underspill begins approximately 2:45pm River re-opens by 7:00pm

Please note all times are approximate and subject to change due to weather and tides.

As the tide continues to come in, a higher level of water will build up downstream of the barrier and create a differential in water level on either side of the gates. Shortly after high water or high tide, the gates will be further rotated by 28 degrees (or roughly 2 metres) into what is called the ‘underspill’ position.

The underspill is when the gates have been raised 90 degrees. The Barrier is fully closed in the ‘defence’ position.

Underspill allows the higher downstream water level of the river to rush underneath the gates to shorten the amount of time it takes for the upstream and downstream water levels to equal.

It also creates a ‘white rush’ effect of water behind each of the gates, stirring up the riverbed .

The underspill continues for approximately 2.5 hours.

Forecasting closures

The Environment Agency receives information on potential tidal surges from weather satellites, oil rigs, weather ships and coastal stations. They can forecast dangerous conditions up to 36 hours in advance, and will close the barrier just after low tide, or about 4 hours before the peak of the incoming surge tide reaches the barrier.

They get information from a range of mathematical computer models that forecast expected sea and river levels. This is supplemented by data from the Met Office and real-time information provided by the UK National Tidegauge Network. This hydrological and meteorological data is fed into the control room every minute from a wide network of tide, river, pressure and wind gauges.

The decision to close, or not, is based on a combination of 3 major factors:

  • the height of the tide (usually a spring tide) measured at the Thames Estuary
  • the height of the tidal surge, which naturally accompanies each tide
  • the river flow entering the tidal Thames, measured as it passes over Teddington Weir

Find up-to-date data for river and sea levels at the Thames Estuary and Teddington Weir.

The barrier has no individual trigger level for closure. The closing process is guided by a mathematical matrix that considers the river flow, tide and surge at the time. The final decision for closure lies with the Thames Barrier Duty Controller.

How the Thames Barrier works

The Thames Barrier spans 520 metres across the River Thames near Woolwich, and it protects 125 square kilometres of central London from flooding caused by tidal surges. It has 10 steel gates that can be raised into position across the River Thames. When raised, the main gates stand as high as a 5-storey building and as wide as the opening of Tower Bridge. Each main gate weighs 3,300 tonnes.

The barrier is closed under storm surge conditions to protect London from flooding from the sea. It may also be closed during periods of high flow over Teddington Weir to reduce the risk of river flooding in some areas of west London including Richmond and Twickenham.

The Thames Barrier will then remain closed over high water until the water level downstream of the Thames Barrier has reduced to the same level as upstream. This is a managed process to provide for different circumstances, and takes about 5 hours. The Thames Barrier is then opened, allowing the water upstream to flow out to sea with the outward-bound tide.

You can watch a video that shows how the Thames Barrier works:

a video of how the Thames Barrier works

Thames Barrier closures

The Thames Barrier has been closed 193 times since it became operational in 1982 (correct as of June 2020). Of these closures, 106 were to protect against tidal flooding and 87 were to protect against combined tidal/fluvial flooding.

Bar chart detailing number of Thames Barrier closures since 1983

Thames Barrier closures since 1983

If you have an enquiry about the Thames Barrier, or would like to receive a project pack, email:

The future of the Thames Barrier

The Thames Estuary 2100 plan sets out how flood risk will be managed in the Thames estuary to the end of the century and beyond. It also recommends what actions the Environment Agency and others will need to take in the short term (the next 25 years), medium term (the following 15 years) and long term (to the end of the century).

The plan is based on current guidance on climate change, but is adaptable to changes in predictions for sea-level rise and climate change over the century.

More information can be found on the Thames Estuary 2100 page .

Visiting the Thames Barrier

New Thames Barrier cafe and information centre

New Thames Barrier cafe and information centre

Information Centre

The Thames Barrier Information Centre is a small, informative exhibition about the past, present and future of the Thames Barrier. It explains the flood risk to London and the history and environment of the River Thames. There is a working model of the Thames Barrier, a film on the construction, a virtual technical tour film and interactive displays. Last entrance is 30 minutes before closing (see above opening times).

Please call 0208 305 4188 or 0208 854 8028 for information about disabled access.

Thames Barrier Café and Information Centre closed until further notice

Update 6 July, 2020

Following recent COVID19 advice and guidance from the government regarding cafes and exhibitions, the current restrictions mean we are still unable to open the Thames Barrier Café and Information Centre.

We are monitoring the situation continuously, and will update our website as and when anything changes.

As of Monday 6 July, our outside toilets downstairs and disabled lift will in use 7 days a week between 9.00 am and 5.00pm.

For further enquiries, please telephone 0208 305 4188 or email

Opening times

Date Open Last entrance to Information centre Closed
Spring and summer opening to be announced      
Thursday to Sunday 2 November 2020 to 28 March 2021      
Thursday to Sunday 29 March 2021 to 31 October 2021      

Self-led visit to the Information Centre

The prices for these are:

  • Adult £4.15
  • Senior (over 60) £3.65
  • Child (under 16) £2.65
  • Family ticket (up to 2 adults and 3 children) £11.00
  • Disability discount offered on above prices

Packages for groups and schools

Bronze group talk

A guide and admission to the Information Centre. Your guide will cover topics including the history of the river and the risk of flooding in London, the environment and wildlife of the Thames. Time approx. 1.5 hrs. Price from £140.00 per group up to 35.

Silver group talk

Guide, admission to the Information Centre and presentation about the Thames Barrier in our conference room. Refreshments or lunch can be added to this package. Time approx. 1.5 hours (plus 30 minutes if catering ordered) Prices start from £200.00 per group up to 35.

Child/student Gold group talk

Guide, admission to the Information Centre, presentation on the Thames Barrier and choice of activity game. Time approximately. 2.5 hours. Price starts from £230.00 per group up to 35.

Adult and Senior Gold group talk

Guide, admission to the Information Centre and a technical presentation on the Thames Barrier. Time approximately 2.5 hours. Price starts from £250.00 per group up to 35.

The View Café

The View Café offers refreshments, snacks and light lunches with an outside balcony, picnic benches and play area. There is parking on site for cars and coaches, parking fee applies.

Pre-ordered afternoon tea

A selection of sandwiches, cakes and scones with jam and cream with tea or coffee. Price £13.00 per head.

Conference room hire

The Thames Barrier View Conference Centre also has rooms to hire that offers spectacular views of the Thames Barrier and River Thames. The rooms are light and spacious and offer various room layouts to suit all occasions.

There is a room hire for up to 60 people, with catering for functions such as:

  • conferences
  • meetings
  • receptions
  • workshops
  • wakes
  • group talks
  • lunches and afternoon teas

For prices please telephone 0208 305 4188 or email Please complete the Booking Form for all bookings.

Getting to the Thames Barrier


Charlton station is situated on Woolwich Road and is approximately a one mile walk from the Thames Barrier Site. Woolwich Dockyard station is situated near Church Street and is within walking distance. Woolwich Arsenal station is the most convenient station to take a taxi to the Barrier Site.

London Underground North Greenwich (Jubilee Line)

The station is approximately 2 miles from the Thames Barrier and only 5 minutes by taxi or bus (161 & 472).

Bus Routes

Bus No’s 177 and 180 via Greenwich (stop at the top of Eastmoor Street). 161 & 472 from North Greenwich tube station.

London City Airport

The City Airport is situated in North Woolwich only a short distance from the North Woolwich Ferry crossing.

Further information

Any questions, please telephone 0208 305 4188 (Monday to Friday) or 0208 854 8028 at weekends.

Published 25 April 2014
Last updated 29 September 2020 + show all updates
  1. Additional information added to Annual Full Tide Test Closure section, detailing limitations resulting from coronavirus for the October 4 closure Dates deleted for closures that have already taken place.

  2. Out-of-date link deleted 07/07/20

  3. Café and information centre opening times updated 6/07/20

  4. Barrier opening history updated 16/06/20

  5. Opening times for café and information centre updated 24/03/20

  6. Note about closure of café and information centre added 19/03/20

  7. New dates for forthcoming scheduled closures added 12/02/20

  8. Amendments to 2020 opening times added 24/12/19

  9. Opening times and contact email address updated 12/12/19

  10. Disabled access information updated 17/10/19

  11. Visitor centre information updated 16/10/19

  12. Note added 08/10/19 advising disabled lift to visitor centre out of order

  13. Updated to reflect that today's full test closure has been cancelled.

  14. Information updated 19/09/19

  15. Changes to opening times and test closures, additional information about full test closure added 30 August 2019. Additional information about disabled lift not working added 04/09/19 Additional information and link added 13/09/19 Opening times and information about disabled lift added 06/09/19

  16. Update to disabled lift opening made 6 August 2019.

  17. New dates for test closures added 25 July 2019.

  18. Data uploaded 3 July 2019.

  19. Amendment to the disabled access information 9 May 2019.

  20. Updates to information Centre made 9 May 2019.

  21. Amendments made to opening times and group bookings section 17 April 2019.

  22. Updates to data and graphics made 27 March 2019.

  23. New graph and data uploaded 28 February 2019.

  24. Changes made 9 January 2019.

  25. New booking form uploaded 18 December 2018.

  26. New Booking Form uploaded 13 December 2018.

  27. Test closure cancelled for 13 December 2018.

  28. New opening times added on 20 November 2018.

  29. Update to closure dates made 29 October 2018.

  30. New information added 8 October 2018.

  31. Updates to information made 27 September 2018

  32. Information on disabled toilet added.

  33. Timings for the Thames Barrier annual closure added

  34. Additional test closure dates added 31 July 2018

  35. Disabled lift now working.

  36. Details on the opening of the new Cafe and Information Centre.

  37. New information for the Thames Barrier Information Center and Cafe.

  38. New dates for test closures added.

  39. Refurbishment of cafe delayed until June 2018.

  40. Numbers of closures updated.

  41. Two closures added to closure total.

  42. Correction to barrier closures.

  43. Information on the refurbishment of the Thames Barrier Information Centre and cafe.

  44. Data update 10 October 2017.

  45. Information about finding out if the Thames Barrier is closed via Floodline removed as service is no longer available.

  46. Thames Barrier Annual closure event information removed.

  47. New test closure dates, Cafe closing for refurbishment dates changed and warning to users of wheelchairs at the Annual Closure about access to river bank.

  48. Cafe opening at 9am on the Annual Closure day.

  49. Cafe opening times updated

  50. New information on Thames Barrier Annual Closure

  51. New times added for cafe and information centre.

  52. Taken out that the disabled lift is broken as now fixed.

  53. Information on disabled lift being out of order.

  54. New dates for Thames Barrier closures and group talks added

  55. Notice that the Information Centre will be closed between 30 October 2017 and 28 January 2018 for refurbishment.

  56. Updated opening times to cafe and Information Centre, new group talks dates added

  57. Tall ships dates and the 2017 Thames Barrier annual closure date added.

  58. Cafe opening times updated.

  59. Updated information on group talks

  60. New opening times added.

  61. New information added.

  62. November to March closure dates and information about the Open Day on 2nd October added.

  63. Updated closure dates.

  64. Special offers for Father's Day at the Information Centre.

  65. New group bookings added.

  66. New Thames Barrier Information Centre group talk dates, price list and booking form added.

  67. Notice of event at Information Centre.

  68. Annual closure times for 2016 added.

  69. Updated timetable for group talks.

  70. Visiting the Thames Barrier section has been updated.

  71. Details added about the annual closure.

  72. Details on the annual closure have been added.

  73. Updated closure times and group talk sessions.

  74. In summer 2015, the Information Centre is open 7 days a week during the school holidays.

  75. The test closure dates have been updated, and there is a new link to our blog posts.

  76. New information for group tours of the exhibition centre.

  77. New Barrier closure information.

  78. Updated planed closure dates

  79. Thames Barrier Information Centre prices from April 2015.

  80. Information on group talks added.

  81. Updated 'forecasting closures' section.

  82. Added new closure dates for 2015.

  83. First published.