The Menai Strait


The Menai Strait, or Afon Menai as it is known , is the channel that separates Anglesey from mainland Wales.  It is connected to the mainland by Thomas Telford’s Menai Suspension bridge and Robert Stephenson’s Britannia Bridge.  The Strait varies in width from about a couple hundered meters to three quarters of a mile.  The central region (between the two bridges) is known as the ‘Swellies’; this is a dynamic environment with a strong, tidal flows, rapid currents and big back eddies.  From the Anglesey side, there are lovely views of the Snowdonia and Carneddau mountain ranges, Conwy Bay and the towns of Bangor through to Caernarfon.

The Strait is a major geological fault, forming a transition between Anglesey and the similar-aged  rocks of North Wales. It was shapped by ice.  This unmistakeable feature was formed by glaciers flowing from Snowdonia, and by the Irish Sea ice stream which covered Anglesey during the last ice age approximately between 11,000-22,000 years ago. The Strait is also a marine Special Area of Conservation (SAC), with a rich variety of habitats including sea inlets and estuaries, mud and sand flats, lagoons, salt marsh, shingle beaches, sea cliffs and submerged limestone reefs (


Oceanography of the Menai Strait

The oceanography of the menai straits in quite unique, with its monstrous diurnal tides which flood in twice daily up the amphitheatre that is the straits. The tides have a fierce pace have the second largest tidal range in the world only seconding to the bay of fundi in Canada. The rich marine life that these strong tides cater for and provide an abundant nutrient mass for support the ecosystem well.

The Menai strait covers 16 miles long  and is 1200m wide at its widest point, depth of the channel at its deepest point is 40m+  and its shallowest is can be a meter at high water on the shallow banks . Spring tides speed can be upto 10m + Rise and fall. The waters of the strait are slightly inhospitable when they are at their worst, and navigation can be a little treacherous, If you’re a new sailor to the area. Napoleon once famously said that if you could navigate the waters of the Menai straight under a sail powered craft that you could sail anywhere in the world.

The diurnal tides that rip through the deep scoured channel that is the Menai fault bring with them a diverse amount of nutrients and a host of wonderfull marine life species also. Its is an ecological underwater rainforest and haven.

It is home to once of the best Oceanography university’s in the world called Bangor School of ocean sciences. Its where some of the worlds top environmental, geological and oceanographic students come to cut their craft as did I now almost 10 years ago.

There is a great video here that shows now a full detailed bathymetric map of the Menai strait, showing its depth in a colour coded style. This was mapped by the SOS (School of Ocean sciences) and Seacams.


“For centuries, travelling to Anglesey from Wales mainland was very dangerous. The tide coming from two directions creates strong currents and whirlpools which can easily sink small boats, and there are also four tides every day. Drovers would swim animals along the Menai when the tide was out. At low tide, there is only 18 inches of water in places, but its very difficult to walk across the sandbanks and people can get easily stranded.

Several ferries used to cross the Menai in different places, but they would often capsize, or sink, and lives were frequently lost. The worst case was in 1785, when a boat carrying 55 people went aground on a sandbank on the south side of the Menai Strait. As they tried to release the boat, it began to fill with water. Rescuers in Caernarfon heard of the crisis, but with the strong wind and the night closing in, and the danger of itself running aground, the lifeboat did not manage to reach the stricken boat. Only one person survived.

When Ireland was joined with Great Britain in the Acts of Union in 1800, there was a great increase in the numbers that wished to cross the strait to travel to Holyhead and then on to Dublin. The road between London and Holyhead became very important, as it was the connection between Ireland and the Parliament in London. The journey from London to Holyhead took 36 hours; when Menai Bridge opened in 1826 the journey time reduced to 27 hours! By today, using motorways, modern cars and Menai Bridge the journey can be completed in less than seven hours!”


The menai strait is famous for its two bridges the Stevenson’s Britannia bridge (near) and the Thomas Telford Suspension  bridge (far).

Both bridges- beaumaris lifeboat
The Swellies in-between the two bridges and a full er view of the means straits. Image by Beaumaris lifeboat.

Telford Suspension Bridge

The Thomas Telford bridge is the oldest of the two bridges and the most iconic of the two. The bridge was officially opened on the 30thof January 1826. Over the years the bridge has been changed quite a bit.

A steel road replaced the original wood road in 1893. As modern vehicles became more common, the maximum weight of 4.5 tonnes, started to become a burden, with service buses having to ask it’s passengers to walk across the bridge! Between 1938 and 1940, iron chains replaced the original steel chains and in 1999 the bridge was closed for a few weeks to replace the road and strengthen the bridge.

The design and architecture surrounding the Telford suspension bridge is a testament to the iconic Victorian engineering of its day.

Thomas Telfords suspension bridge Image by Kris Williams

Britannia Bridge

The popularity or rail travel increased in the 19th century, and it became obvious that trains needed to cross the Menai Strait. As the planning of a railway to Holyhead began, there was a suggestion that a railway should cross the present bridge. The carriages would have to be uncoupled on one side of the bridge, and be pulled, one at a time, by a horse across the bridge, and recoupled to another train on the other side. This idea was put to one side, and Robert Stephenson, the son of the railway pioneer George Stephenson, got the chance to build a new bridge with the help of William Fairbairn and Eaton Hodgkinson.

Like the previous bridge, it had to have 100 feet of clearance underneath to allow for the sails of tall ships, but it also had to be strong enough to hold rails and the weight of a train and several carriages. Even today such a project would be difficult.

It was decided to build a tubular bridge, a revolutionary idea at the time. There would be two iron tubes, each 472 feet long, one for each of the train lines. Originally it was believed a chain would be needed to support to bridge, similar to a suspension bridge, but after having experimented it was decided the bridge would be strong enough without.

brit bridge by oliver mills
Britannia bridge Image by Oliver Mills

Adventure and Activities

With so much of the emphasis around or on the water so much time on the Menai Strait is spent on the water here are some of the top activities we get up to on the Island



The Menai straits is renowned for its amazing seasonal fishing. By seasonal I mean in every season these are very good species to catch. Whether its summer fishing for Mackerel, Bream or Bass fishing or whether its winter fishing cod, whiting, conger or coalfish your after- the straits because of its biodiversity has something for every angler.

Its quite unique from a viewpoint of its tidal range and nutrient capacity the fish flock to the region. The biodiversity in the straits is so diverse from fresh water outlets flowing in all long the straits (which are a blog or book completely by themselves!) see our blog on Fly fishing in north wales. The rivers Alaw, Cyfni and Sioent all flow in to the straits which provides all the estuarine water fish a place to feed and live also for such fish such as Salmon and Seatrout. These are Wales best kept secrets!

For more on Fly fishing see this article. You can both partake in Shore fishing and boat fishing on the straits an there are a number of locations such as Beaumaris pier,  Bryciencyn and Menai bridge. Want Fishing lessons click here as we will be running some group or 1-1 tutorials in 2018. For Boat fishing –Head over to Stradia website and go book a day on the water

fishing anglesey
A days sea fishing on  the Menai strait  : Image by www.


Sailing the menai straights has always been a very unique experience and draws some of the best sailors in the world to its troublesome waters to test their metal against the tides and currents, intertidal waters created by the monstrous amplitude the tides, and weather create. There are three sailing clubs along the shores of the Menai Straits, The Royal Anglesey Yacht club at Beaumaris, The Royal Welsh Yacht club at CaernarfonPorth Dinorwig yacht club in Porth Dinorwig near Felinheli. They are very bust throughout the season and host many regattas through the spring, summer and autumn season. With many lovely anchorages just out side the menai straights and alos in the towns of menai bridge and beaumaris for yachy enthusiasts there is much to do and places to see. Sailors can pick up a swinging mouring for the night, row ashore and have a campfire on the beach, vivist a ocal pub we recommend The Garddfon, The Liverpool arms and The Gazelle Hotel. Also see our pages on Sailing in north wales.Want to learn to sail? Head to Plas Menai on the Menai Strait for either dinghy or Yacht training sailing.

sailing on the strait- yachts and yachting
Regatta sailing in the summer season on the Menai strait. Image by


The meani straight sis very renound for its scuba diving and has been at the forefront of the sport for the best part of 40-50 years even since the first onste of scuba breathable lung technology on the market, the Gwynedd Subaqua club was one of the first UK dive centres and can boast easilt the closest proximity to all the bounty of ship wrecks that litter the seabed in the local vicinity.

Anglesey is a hive for Ship wrecks of all manners and has been for many hundred of years, probably longer. There is a wealth of ship wrecks on the seabed that surround our Island the light houses for many hundres of years have tried their best to keep ships away from the steep jagged nature of our coast- but sometimes mother nature wins.

A plethora of wrecks await all divers as long as the visibility provides the opportunity to see them. We have such a rich coastal nutrient base which in turn creates a very strong algal bloom in summer months which conversely is the best time to dive! But with this happening later in the season we usually can sneak in a dive or ten before this.. Contact Gwynedd subqua for more details on diving locations, gas and much more also see our Pages on Scuba diving.  For Scuba diving kit expertise visit Anglesey Divers.

scuba straits - scuba diver magazine
Scuba diving in the Menai strait on a good days visibility ! Image by

Boating & water sports

Boating of any kind is very popular on the menai straights, as previously motioned sailing is a very popular pastime here in north wales as while as well as the menai straights with its amazing tides currents and bathymetry to navigate through. There are many other water sports that are very popular such as Sea kayaking, Stand up paddle boarding (SUP) and windsurfing.

psyched paddle boarding
Sian from Psyched paddle boarding on the Menai strait cruising around! Image by


To do list in around the Menai Straits :

Walk Beaumaris pier with an ice cream- newly refurbished!

Take a walk along the shores so of the Menai straights around Telfords bridge and watch the tide ebb by underneath such an iconic structure- it really is beautiful down out with the tides!

Go visit Plas newydd and take a walk through their picturesque gardens and foreshores of the straits.

Locals Tip : Head over to the sixth Century church, St Tysilios on church island in the Menai straits, take a walk around its permitter and take in some its beauty on a summers eve. A good clip of it here on youtube.

Go visit Beaumaris castle and check out its amazing architecture.

Head over to Puffin Island on a n evening cruise to see the wildlife.

Go and spend an afternoon exploring  Penrhyn Castle just off the shores of the Menai strait.

Get a crabbing line a bucket some bacon and head to the pier (either Bangor or Beaumaris) for a spot of crabbing!


Main Towns on the Menai strait 

Menai bridge




Y Felinheli / Porth Dinorwig


Top Awesome Places to stay on the shores of the Menai straits

Cheateau Rhinaffa – A classic gothic castle style retreat- Simply beautiful

Gazelle hotel-A classic among mariners, you can park your your Rib and nip for a drink in the summer

The Anglesey Arms – A lovely warm feel to this place, nice bar and lovely dining area

AirB&B- Menai Bridge

Menai Holiday Cottages – A great local based company with lots of character filled Holiday cottages in north Wales on their books.

North Wales Holiday cottages- Another great accommodation on the island proving excellent holiday cottages in north Wales.


Activity top 3 to do list

Go charter boat fishing with Stradia from Beaumaris pier area and catch some fish!

Rib ride up and across the straights at warp speed whilst taking in the beautiful scenery..

Stand up paddle board (SUP) experience up the Menai straits with Sian Sykes (she is getting rather famous in these parts from teaching Robson green on ITV’S Coastal lives (link below!))  Psyched paddleboarding


Where to Eat

Head to Dylans for a light lunch and drink with a view over at Menai bridge on their veranda

Go to The red boat ice cream parlour in Beaumaris and treat yourself  to a monster gelato!

Dog Friendly Eats on the Menai Strait

Trip advisor – is perfect for this.


Top 3 Popular attractions on the Menai Strait

Seazoo – Amazing under water aquarium that has the most amazing under water fish life and finds

Halen Môn – Our world leading Salt company based on the shores of the Menai Strait

Plas Newydd – Ran by the national trust this Stately home is set in beautiful grounds


Local food from the Menai Strait

Menai mussles– Some of the best seafood in Europe

Halen mon – possibly the best sea salt in the world?!

Menai Oysters – Say no more! Delicious ..


Recent TV programmes to watch on the Menai Strait :

The Strait – ITV 

Country File 2018- BBC

Robson green- Coastal Lives 


Books and Photography 

Some stunning photography of the Menai strait, front cover image by Kris Williams a local photographer who spent his days adventuring around north Wales shooting some amazing pictures he has a book out and his Instagram channel @JixxKris

Some of the better books on the Menai strait include The Menai Strait by Gwyn Parry Hughes, Crossing the Menai by bridge books and Admiralty charts for the Menai Strait.


We may be running some Fishing & Foraging 1-1 and small group courses in 2018 on the shores so the Menai straits if  your interested in getting back in sync with nature then get in touch with us! The listing will be up on the website soon!


Extended reading list and useful links :

Getting here! By car head to north Wales A55 come off at Jct 9

Some more beautiful photos of The Menai Strait

Amazing Home for sale  on the shores of The Menai Strait

Porthaethwy / Menai bridge town info

Guide  to The town of Beaumaris 

Food shop? Waitrose is quite convenient

Weather guide – hover cursor over Caernarfon airport!

Whats on guide – in progress!

Best coffee shops – & Our favourite! 

Secluded swim spot out of the tide near Llangoed, easy access via a slip!

Great camper van spot and good spot for fishing (keep that under your hat!)

Nice walks on the Menai straits

Art Galleries on the Menai straits


We hope this guide is useful for you guys – if you have a secret spot you love, someplace lovely to eat , activity or just some cool info to add to this blog we would love to hear from you! – leave a comment below and well reply! N

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