Where the data comes from

Government and regulators

Bathing water designations, annual classifications, in-season sampling, daily pollution risk forecasts, pollution incident notices and tide gauge readings come from the Environment Agency, Natural Resources Wales, the Scottish Environment Protection Agency, and the Department of Agriculture, Environment and Rural Affairs in Northern Ireland.

Contains public sector information licensed under the Open Government Licence v3.0.

Contains Natural Resources Wales information © Natural Resources Wales and Database Right. All rights reserved.

This uses Environment Agency flood and river level data from the real-time data API (Beta).

Ireland

Bathing water restrictions and sample results come from the Environmental Protection Agency and the local authorities, through beaches.ie. Tide predictions come from the Marine Institute, under CC BY 4.0.

Water companies

Live storm overflow status comes from the eleven water companies that publish it: Anglian Water, Northumbrian Water, Severn Trent, Southern Water, South West Water, Thames Water, United Utilities, Wessex Water, Yorkshire Water, Welsh Water and Scottish Water. Each publishes its own data under CC BY 4.0.

Weather, sea and tide

Weather data by Open-Meteo.com, under CC BY 4.0. That covers rainfall, the seven day forecast, wind and gusts, the UV index, sea temperature, wave height and swell, and the modelled sea level this site uses for the tide in Britain.

The measured sea temperature shown on beaches near a wave buoy comes from the Cefas WaveNet network. Hull et al (2023). WaveNet near real-time data feed — from the past 48 hours. Cefas, UK. V1. doi: https://doi.org/10.14466/CefasDataHub.142. Contains public sector information licensed under the Open Government Licence v3.0. Seventeen buoys report a water temperature, they are moored well out in open water, and the feed is near-live telemetry that Cefas have not quality checked — so a reading is shown only where a buoy is within 40 km and the line from the beach to it stays over water, always with its distance, and never as the temperature at the beach itself. The second test matters more than the first: the Poole Bay mooring is 36 km from Ventnor, but the line between them crosses the Isle of Wight, so Ventnor is told nothing. The ground under every line is checked with elevation data from Open-Meteo.com.

The sea state words printed beside our own on each beach page are WMO Code Table 3700, published by the Met Office for the Shipping and Inshore Waters forecasts and by Met Éireann for Irish waters. It is used here only to say what the forecast would call the same water, never to decide anything.

Beach awards

Blue Flag, the Seaside Award, Scotland’s Beach Award and the Green Coast Award come from the bodies that give them: Keep Britain Tidy in England, Keep Wales Tidy in Wales, Keep Scotland Beautiful in Scotland, Keep Northern Ireland Beautiful in Northern Ireland, and An Taisce on behalf of the Foundation for Environmental Education in Ireland, where the award is published as a field on each bathing water by the Environmental Protection Agency. Each list is read from the awarding body’s own published list, and the date it was read is recorded with it. The award logos are trademarks of those bodies and are not reproduced here: the flag beside an award on this site is drawn here, and the award is named in words.

Lifeguards

RNLI lifeguard unit locations. Contains Open Data licensed under the GIS Open Data Licence. The data carries a location and nothing else — no patrol dates, no season, no hours — so this site never says a beach is lifeguarded today, and never says a beach has no lifeguard, because a council or surf club patrol is not in it.

Maps and places

Map data and waterfall locations © OpenStreetMap contributors, available from https://www.openstreetmap.org/ under the Open Database Licence. County outlines come from the Office for National Statistics under the Open Government Licence, and from OpenStreetMap.

What has been done to the data

It has been changed. That is the point of the site, and the licences require it to be said plainly. Readings from many sources are combined into one verdict for each place. Spill records are counted into windows. A tide curve becomes a sentence like “going out, low around 14:50”, and in Britain that curve is shifted by an offset worked out from the nearest tide gauge. Wave figures are dropped where the nearest point the model holds is more than twelve kilometres away: a wave height is a claim about this beach, and Instow was handed Croyde Bay's open Atlantic from seventeen kilometres up the estuary. Sea temperature is kept out to twenty, because it is a smooth field — measured across every published cell, two points twelve to twenty kilometres apart differ by a quarter of a degree. None of this is the responsibility of the people who published the original data.

The sources make no warranty about their data, and neither does this site. Data is provided as it is found.

Photographs

Photographs come from Wikimedia Commons and are credited individually on the page they appear on, with the photographer and the licence.

This site

Can I Swim? is not connected to any of the organisations above, and nothing here is endorsed by them. It is one person reading what they publish. The code that collects the data is open source.