The Menai Strait
Photo : Tim Snow

The Menai Strait

The Isle of Anglesey is separated from the Welsh mainland by the Menai Strait (Welsh: Afon Menai) which runs in a roughly North East – South West direction and is about 18.5miles (29.8km) in length

The Menai Strait creates an income for so many business’s and is also a massive playground for locals and visitors alike. The strait provides an interesting and relatively sheltered stretch of water between the harbours of Conwy at the north-east end and Caernarfon to the south-west.

Aber Menai Point

The south western approach of the Menai Strait starts at Aber Menai point on the Anglesey shores, which is opposite Fort Belan. The northern eastern end of the Strait start at Puffin Island and stretches across towards Penmaenmawr, this is the widest part.

Ex bombs loaded, Fort Belan

Caernarfon Castle with pleasure boat entering the harbour


The Royal town of Caernarfon, where Prince Charles was invested at Caernarfon castle is the first town along the Menai Strait. This magnificent castle was built by Edward I.

The harbour at Caernarfon is one of the main storage places for many of the local yachts up this end of the Strait.

Along this stretch of the strait you have along sandbank running through the middle.

The entrance to Anglesey Sea Salt

Anglesey Sea Salt (Halen Mon)

This fantastic little business pumps fresh sea water from the Menai Strait to create sea salt.

Using a special process evaporates the water off leaving beautiful Salt crystals which are the packaged and sold all around the world.

Halen Mon can be found in over 22 countries around the world and has been awarded a Protected Designation of Origin (PDO).

The harbour at Y Felinheli

Y Felinheli (Port Dinorwic)

The coastal village of Port Dinorwic was once used to ship Welsh slate all around the world like it’s sister port, Port Penrhyn.

With a railway running from the slate quarries in Llanberis this once industrial port was used to ship dressed slate all over the world.

Now a busy little harbour where boat owners keep their yachts and motor craft with quick and easy access to the Menai Strait.

Lôn Las Menai is the section of cycle track which runs for 6.5 km along a section of the former Caernarfon to Bangor railway trackbed. From the north of Caernarfon it just runs to the north side of Y Felinheli.

The stately home Plas Newydd

Plas Newydd

On the Anglesey side of the Menai Strait after Y Felinheli you will see Plas Newydd the stately ancestral home of the Paget family, now in the care of the National Trust.

This beautiful 16th century home looks straight out onto the Menai Strait, with views up to Port Dinorwic and down to the Britannia bridge.

Plas Newydd is unique as it now uses the sea water from the Menai Strait to heat a 300 year old mansion using a special 300kW marine source heat pump. The special pump which cost £600,000 to install and is the first of it’s size to be installed in the UK.

Fishing by the Britannia Bridge on Anglesey

The Britannia Bridge

The Britannia Bridge was the second bridge to be built to take traffic across the Menai Strait. Built by railway and civil engineer Robert Stephenson.

The original tubular bridge caught fire in 1970 and the tubes that the trains travelled through had to be removed. But this tragic event gave birth to the new Britannia Bridge as we know it now.

With the increase in traffic and the construction of the A55 dual carriageway the road deck was built over the railway line crossing the Britannia bridge.

Looking across the Menai Strait towards the Menai Suspension bridge

The Swellies (Pwll Ceris)

The Swillies or Swellies as it is sometimes known is the body of water that runs between the Britannia Bridge and the Menai Suspension bridge.

This beautiful area of water can be extremely dangerous and fast flowing at big tides.

This section of the Anglesey Coastal Path that runs almost parallel with this part of the Menai Strait is particularly beautiful, with close up views of the island Ynys Gorad Goch which is situated in the middle of the Menai Strait between the two bridges.

Ynys Gorad Goch in the middle of the Menai Strait

Ynys Gorad Goch

Ynys Gorad Goch or Red Weir Island is situated in the Swellies and nearer to the Britannia bridge.

The Island was once used to trap fish and then smoke them. During the 1820’s a trap was built on the Island to catch fish during high tide.

Then as the tide went out the fish were recovered. The fish trap on the island is still visible today.

The Menai Suspension Bridge from the air

The Menai Suspension Bridge

The Menai Suspension bridge was the first of the two bridges to be built.

Started in 1818 and finished in 1826 by Scottish engineer Thomas Telford.

Originally a toll bridge, but freed from toll on 31 December 1940. Built from local limestone sourced from the Penmon quarries at the eastern end of the Menai Strait.

Prince's pier at Menai Bridge

Prince’s Pier

Much of the area around and including Prince’s Pier belonged to the wealthy Davies family, who developed a large timber merchant business, mainly importing timber and exporting slate to North America.

Their warehouses and timber yard were constructed in 1827 and the Prince’s Pier Wharf in 1832.

In more recent times Menter Mon purchased Prince’s Pier and buildings to be developed in conjunction with Menai Heritage. In the spring of 2014 the first phase was completed when the building was fully refurbished and the adjacent pier masters house was converted into offices.

The next phase is to raise funds and build an exhibition space with cafe so that the history of the Menai Strait, its bridges and their history can be shared from this location to visitors of Anglesey and the local community.

RV Prince Madog stops of at St. Georges Pier in Menai Bridge

St. George’s Pier

St. George’s pier in Menai Bridge, although now totally modernised is one of the original piers on the Menai Strait where passenger ships would arrive in the mid 1800’s and early 1900’s bringing passengers to the local area.

Pleasure steamers from the Liverpool and North Wales Steamship company would stop of here, Garth pier and at Beaumaris pier.

Today the pier is frequently used by the nearby RibRide boat tours company and is a permanent home for the School of Ocean Science research vessel RV Prince Madog.

School of Ocean Sciences

Since the early 1950’s Bangor university’s School of Ocean Sciences has been based in Menai Bridge. Situated on the shores of the Menai Strait, this is one of the largest university Marine Science departments in Europe.

Port Penrhyn packed with boats

Port Penrhyn

Another former industrial port from North Wales slate history. This port is now used by leisure craft and the mussel dredgers that farm and fish the mussel beds between Gallows Point and the Gazelle hotel opposite Bangor Pier.

Originally the trains on the narrow gauge railway brought the slate down from the Penrhyn quarry in Bethesda to the Port where it would have been shipped all over the world.

Trwyn Du lighthouse and Puffin Island

Puffin Island

Puffin Island, also known as Ynys Seiriol marks the eastern entrance of the Menai Strait.

This now uninhabited island can be seen from the beautiful Penmon Point or can be visited by one of the Rib Rides at Beaumaris or Menai Bridge.

Puffin Island is popular for its population of seabirds like razor bill, cormorant, shag, black guillemot, guillemot and kittiwake’s, not forgetting its Puffins as well!!