All swimming spots › Isle of Anglesey, Wales
Can I swim at Cemaes?
Isle of Anglesey, Wales · Coastal
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Before you get in
A red flag means do not go in, whatever this page says.
If you get into trouble, float on your back until the cold shock passes. Full advice below.
In an emergency call 999 and ask for the Coastguard, or 112 in the Republic of Ireland.
Water quality today
The last fortnight
What this verdict covers
Independent site, not an official one. This verdict is about water quality. It does not tell you whether the water is safe to get into today.
How it has been rated
The annual classification for 2021 to 2025. Each one is calculated from samples taken over up to four bathing seasons, so these overlap and none of them describes today.
Every sample, 2023 to 2026
45 samples, 2023 to 2026. The highest E. coli count in them was 4,600 per 100ml, on 15 September 2023; the standard for Excellent is 250 or below and for Good 500 or below.
One bar for each sample, oldest on the left. The taller the bar, the more E. coli that bottle held.
The scale is the same on every beach on this site, which is why a clean beach looks flat — the bars are measured against the standard rather than against that beach’s own worst day. Hover or tap a bar for that day’s figures. A single count over a line is not a failed beach. The classification is worked out as the 90th and 95th percentile of four years of samples, so one bad morning does not decide it — and one good morning does not either. 4 of these are above the Good standard, so they are pinned to the top with a notch rather than the chart stretching to fit them.
What these bacteria mean for you
Neither one is what makes people ill by itself. They are markers: they live in the gut, so finding them means sewage or animal waste has reached the water, and whatever else came with it is likely there too.
The usual way to catch something is swallowing the water, and the usual result is a stomach upset. Ear, eye, chest and skin infections are the other common ones. Putting your head under and swimming with an open cut both raise the odds.
The riskiest time is the day or two after heavy rain, when storm overflows discharge and rain washes off farmland — including at beaches rated Excellent for the rest of the season. That is the whole reason this page shows you rainfall and discharges alongside the grade.
Cemaes was rated Sufficient for 2025, the minimum passing grade in the Bathing Water Regulations. That grade comes from bacterial samples taken over several seasons, so it describes the beach's record rather than the water on any given day.
Natural Resources Wales issues a daily pollution risk forecast during the bathing season for 15 of Wales's 114 bathing waters, and Dŵr Cymru publishes live storm overflow status.
The regulator records this as a bathing water whose quality can be affected by heavy rain, which is why rainfall in the last 24 hours is shown above.
The rest of its file
What the regulator holds for this place. None of it describes the water today.
- Water
- Coastal
- Area
- Isle of Anglesey, Wales
- Monitored outfalls within 5km
- 2 (nearest 0.4km)
- Affected by heavy rain
- Yes, per the regulator
Sea, wind, tide and weather
The sea and the weather here today and for the week ahead. Not the water quality verdict above.
Today
Rain, the week behind and ahead
The weather for the week ahead
Where it is, and what discharges near it
Directions to this bathing water
That is Natural Resources Wales’ sampling point, which is at the water rather than at a car park. Your maps app will take you to the nearest road it can reach.
The nearest mapped car park is about 80m away in a straight line. That is not a walking distance: OpenStreetMap knows where the car park is and nothing about the path, which may be longer, steeper or not there at all. It is tagged as charging a fee, as the mappers wrote it.
What is mapped at this beach
- Toilets about 80m away — free
- Caffi Bach - Traeth Mawr about 100m away
Straight-line distances from OpenStreetMap, not walking distances, and only what volunteers have mapped — something missing here may still be there.
Getting here without a car
- Nearest bus stop Cemaes Post Office (after), High Street, about 250m away
Straight-line distances to where the stop or station is, from the national registers of them. That a stop exists is not a promise that a bus calls at it — timetables are somebody else’s data and this page does not read them, so check the operator before you rely on it.
What the regulator says about this beach
From Natural Resources Wales’s published bathing water profile for 2014. It describes the place and its catchment, not today’s water — and this profile is 2014, so treat the history and the works described in it as that old.
The beach itself
Measuring approximately 350 metres, facing north into the Irish Sea, Cemaes is an enclosed sandy bay, backed by a promenade. There is a concrete jetty in the southwest corner of the bay, which provides a small harbour for leisure craft and some inshore fishing vessels. The water quality sample point is located opposite the car park, approximately 50 metres east of the harbour. The beach lies within the Anglesey Area of Outstanding Natural Beauty and part of the beach is within the North Anglesey Heritage Coast.
What drains into it
The natural drainage (hydrological) catchment immediately surrounding the bathing water is initially urban, being the town of Cemaes Bay, then further into the catchment the land becomes rural. The majority of the catchment is dominated by agriculture, and drained by the River Wygyr, which discharges onto the bathing beach.
More from the profile
What has been done about it
Natural Resources Wales has developed a good working relationship with Dŵr Cymru Welsh Water and liaises regularly to identify problems that could affect bathing water quality. Natural Resources Wales is working with Dŵr Cymru Welsh Water to trial a programme of disinfection at Llanfechell Sewage Treatment Works. This is part of a long term initiative to reduce levels of bacteria entering the Wygyr and ultimately the bathing waters.
The council's part
Natural Resources Wales has been working with Anglesey Council to deal with the septic tank serving the toilet block at the beach. A temporary fix is in place. A connection to sewer is being considered.
Published by Natural Resources Wales under the Open Government Licence. The full profile carries more, including sections repeated for every beach that are not reproduced here.
Other swimming spots nearby
The closest bathing waters on the regulators’ lists, straight-line distance. Each has its own checks and its own verdict.
Check the official source
The regulator’s own page for this bathing water. If it disagrees with this one, believe theirs.
Cemaes's official page at Natural Resources Wales · See it on a map
This page is not official. It reads published data and presents it plainly; if a sign at the beach says otherwise, believe the sign.
If you get into trouble
This is the RNLI’s advice, not ours.
Float. Tilt your head back with your ears in the water. Relax and let your breathing settle. Move your hands and legs gently to stay level. Your legs may sink, and that is fine, everyone floats differently. The first shock of cold water passes in less than a minute, so do not try to swim straight away. Once it has passed, call for help or swim to safety.
Caught in a rip current? Do not swim against it, you will only tire yourself out. If you can stand, wade out of it. If the water is too deep to stand, swim parallel to the beach until you are clear of it, then head for shore. Raise your hand and shout for help.
Nobody publishes a rip current forecast for beaches in Britain or Ireland, so this site cannot show you one. The RNLI has one for its own lifeguards. The public does not. Look at the water before you get in, and look for a channel where the waves are not breaking.
In an emergency call 999 and ask for the Coastguard. In the Republic of Ireland call 112 or 999 and ask for the Coast Guard.
Where there are lifeguards, swim between the red and yellow flags. They put those flags where it is safest that day and move them as the sea changes. A red flag means do not go in, whatever this page says. An orange windsock means the wind is blowing offshore and inflatables should stay out of the water. Most places on this site have no lifeguard at all.
This advice is the RNLI’s. Their Float to Live pages are worth two minutes of anyone’s time.
Use this page elsewhere
One sheet of A4 with a QR code to this page, for a clubhouse, a campsite reception, a surf school or a harbour office. The address is printed underneath in words, so it still works for anybody who would rather not scan a code.
Print a sign for CemaesOr put today’s verdict on your own site.
Put this beach on your own site
A small card showing today’s verdict for Cemaes, updating itself. Paste this where you want it to appear. It loads nothing of yours and sets no cookies, and it costs your visitors about ten kilobytes, most of it the readings themselves.
Click the box to select it all. There is also a feed for this beach, if you would rather be told than have to look.