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Celtic Trail
245 mi / 4-8 days
🇬🇧 4 47
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The Severn Estuary

Bristol The Celtic Trail proper starts on the Welsh Border at Chepstow, but we’ll begin our journey on National Cycle Network route 4 at Bristol.

Sustrans, the charity behind the NCN, has its headquarters there – there’s a sculpture map of the network outside the @Bristol centre in the redeveloped waterfront. Ironically, it’s very easy to get lost following NCN 4 west out of the city, so take our map with you: don’t just trust that there’ll be signs. As an alternative for those with hybrid bikes, NCN 41 follows a lovely woodland path along the south bank of the Avon, crossing over to the north bank via a path on the M5 motorway bridge.

Severn Beach (10mi) After the overspill of Avonmouth, the two routes rejoin at the curious never-quite-resort village of Severn Beach. Follow NCN 4 from here to the original Severn Bridge. Crossing the mile-long bridge on the cycleway is a memorable experience, with the treacherous sands of the Severn Estuary far below you. It’s typically very windy, too.

Chepstow (18mi) Chepstow’s main draw is its imposing riverside castle. The Wye Valley is pretty steep-sided, so your legs won’t thank you for the brief detour. In any case, the next few miles through the Monmouthshire countryside are hilly but well chosen and enjoyably rural, diving down to a little valley church before ambling towards Caldicot on quiet lanes and a roadside cycle path.

Caldicot (25mi) After the useful village of Caldicot, the route heads out on the stark Newport Levels. These are flat, quiet – and desperately windy if you catch them at the wrong time. The lanes run alongside drainage ditches from tiny village to village for ten miles before industrial Newport.

The Valleys

Newport (40mi) You have two choices for your entrance to newport: a prosaic cycle path alongside the busy City Bridge, or the fabulously anachronistic Transporter Bridge, a suspended carriage that takes you across the tidal Usk. This temperamental beast is currently being refurbished and a new visitor centre built.

Those who know the city through the words of its favourite sons, comedy rap troupe Goldie Lookin’ Chain, might be surprised by the variety of its architecture. It’s also an important junction on the National Cycle Network, with the first of many routes up the Valleys leaving the Celtic Trail here.

Getting out of Newport was once the low point on the Celtic Trail, with missing signage and an unattractive route. More recently, a new river bridge has diverted it away from busy city streets, while local Sustrans volunteers have been busy with stickers which guide you safely into the countryside. The city falls away surprisingly quickly, for an enjoyable (though hilly) canter on country lanes for six miles to Machen.

Alternative route: Almost entirely traffic-free, the high-level route from Newport to Pontypridd is worth considering. It leaves Newport on the old Monmouthshire Canal, closed for many years but (slowly) being reborn thanks to the work of volunteers. The Fourteen Locks after the M4 are a canal engineering curiosity, and the towpath to Risca and Crosskeys is beautifully wooded – Little Switzerland in the Valleys. After this, the route follows railway paths all the way to Pontypridd, passing over the restored Hengoed Viaduct before meeting the Taff Trail at Quaker’s Yard. Turn south here for Pontypridd.

Machen (50mi) Here, the Celtic Trail joins a railway path for the first time. Cycleways along old trackbeds are the defining feature of cycling in the Valleys. There was once a time when every valley had a railway, often two, serving the mines, ironworks and hillside towns. Inevitably, with the Valley economies in freefall, Dr Beeching did his worst, and the ’70s saw several old trackbeds reused for fast new roads. Thankfully, many remained untouched, and have since become the bedrock of the ‘Valleys Cycle Network’ – perhaps the densest network of cycleways in Britain.

Trethomas (53mi) The railway signal artwork at Trethomas is a neat nod to this heritage. It’s not railway path all the way, and indeed the route either side of Caerphilly is a little fussy, twisting and turning to keep you away from major roads. That said, the wooded riverside path along the Rhymney River is very pleasant.

Caerphilly (55mi) Caerphilly itself is best known for its spectacular castle, matched only by Caernarfon in its completeness and scale – and the Celtic Trail takes you right through the grounds.

Pontypridd (62mi) Two miles on, the route meets the Taff Trail (NCN route 8, aka Lon Las Cymru). The two trails share a railway path for the run into Pontypridd. There isn’t too much to detain the visitor here, but you can take an inexpensive Valley train into Cardiff from here (or Caerphilly) and spend the evening in the capital.

The next section has some of the finest cycling on the route – in a most unexpected place. “How green was my valley?” As the first 20 miles of today’s route prove, very green indeed. The long climb out of Pontypridd is the hardest on the Celtic Trail before Swansea, a mile-long slog on a country lane. But it does take you back into peaceful countryside for the first time since Caerphilly, with just the occasional Valley village between here and Bridgend. Wind turbines and curious cycle paths across farmland add to the sense of isolation, even though the route is just five miles from the M4.

Alternative route: NCN 47 is at its wildest along here, and the alternative route is best suited to those on mountain bikes or who don’t mind a few judders on their hybrid. There’s no settlement of any size in the 24 miles from Pontypridd to Neath, so make sure you’re watered and fed before setting off. You’ll need your climbing legs, too, as the route falls and climbs for every mountain stream. But if you like your wilderness, this is a superb option to take, taking you through a part of Wales that very few people ever see. Keep an eye out for signs, as it can otherwise be easy to get lost in the maze of forestry tracks.

Blackmill (74mi) The off-road route into Blackmill is all new and thoroughly delightful, a smooth tarmac ribbon through the countryside which replaces five unpleasant miles of A road. Here the route falls back onto the valley floor, a green railway path taking you into the tangle of streets at Tondu. The route emerges onto a railside path, following a live but very little-used railway to Pyle.

The Swansea Coast

Pyle (83mi) All good things must come to an end, and the route from here to Swansea is the most utilitarian part of the Celtic Trail. The brief diversion through Margam Country Park is pleasant, but the infamous gate at the entrance requires you to manhandle your bike through. 

Otherwise, it’s largely unremarkable roadside paths all the way from Port Talbot, the approach to Swansea being particularly dispiriting. Put your head down and get it over with… or cheat and get the train! The creative cyclist could improvise a couple of detours – along Port Talbot’s attractive seafront, for example, or along the Tennant Canal towpath west of Jersey Marine.

Swansea (103mi) The entrance to Swansea is soon forgotten. The compact city centre is worth exploring, and the Celtic Trail chooses a particularly attractive way out through the regenerated harbour, then along the seafront. A bacon roll overlooking the pleasant dock area is an excellent way to start your ride to Carmarthen!

A gentle, steady ascent up the Clyne Valley railway path takes you over to Gowerton.


Llanelli (120mi) It’s the 15 coastal miles from Llanelli to Kidwelly that are the real draw, though. Starting after the Wildfowl and Wetlands Trust reserve, the Millennium Coastal Park provides a beautiful seaside ride dotted with cafés and ice-cream sellers. The surface is smooth tarmac throughout – well, apart from the sand that inevitably blows onto the path. It’s one of the few sections of the Wales Coast Path that is open to cyclists, and greatly to be savoured.

Alternative route: The high-level route diverges at Llanelli, so you have the first part of the Millenium Coastal Park to enjoy. From here, NCN 47 follows a gorgeous railway path into the hills before taking minor roads to Carmarthen. This option has much more of the character of rural Carmarthenshire than the coastal route does, though that inevitably means a little extra climbing. If you’ve had enough of the seaside, it’s a good option to consider.

Burry Port (125mi) The last views of the sea – for now – are at Burry Port. Here, the route now follows a traffic-free path and then minor lanes roughly parallel to the A484. There’s an alternative on unsurfaced tracks through Pembrey Forest, where the trail ambles first though plantation, then through coastal flats, all the while far from traffic.

Kidwelly (134mi) Sleepy Kidwelly is a good marker that you’ve left urban South Wales far behind; arrive mid-afternoon, and you’ll believe there’s nothing going on here but the pubs and their faithful regulars. There’s been barely a climb since Pontypridd, but from here the contours get a little more pronounced.

Carmarthen (147mi) Thirteen miles of country lanes take the Celtic Trail into Carmarthen, with a lovely seaside stretch around Ferryside affording fine views. Carmarthen, the gateway to south-west Wales, is a traditional market town and an excellent overnight stop. With its direct trains from London and Bristol, it’s also a suitable break should you be splitting your journey into several visits.

The Celtic Trail in Carmarthenshire and Pembrokeshire has an entirely distinct character from the semi-urban route of Newport, Pontypridd and Swansea. Gone are the miles of railway track, the forest paths and the winding suburban routes. From here, it’s country lanes (almost) all the way.

And it’s much hillier. Each river cleaves a valley as it falls into the sea, and as the Celtic Trail valiantly attempts to follow the coast, it climbs out of every one of them. It’s not gruelling on the scale of the C2C or Lon Las Cymru, but neither is it a ride through the park. As ever in Wales, permit yourself an exasperated sigh that the valleys are colonised by busy main roads, while those of us on more responsible transport are forced up onto the hills.

That said, Carmarthenshire is a lovely county, and these little lanes are the best way of exploring it. The steep climb out of Carmarthen is a rude awakening, but when you reach the top, there’s a real sense that you’ve escaped into rural Wales. So it continues all the way to Pembroke.

Alternative route to Fishguard: From Carmarthen, the high-level route (NCN 47) takes a direct line to Fishguard – shorter, but so much more remote. The blue stones of the Preseli Hills are believed to be the source of Stonehenge, and it’s this unvisited country that NCN 47 crosses on tiny, winding lanes. Yes, there are hills; many of them. But our recollections of the ride are of stone circles just metres from the road; the tin-build Tafarn Sinc and its cheery home-cooked food, manna after a day’s cycling; a remote village where we were the only ones speaking English; old enamel signs on wooden garage doors; and wide, open views with barely a house in sight. Few places in Britain feel so undiscovered. Should you take this option – and we strongly suggest you consider it, perhaps as a return route from Fishguard – then consider a brief detour between Puncheston and Fishguard. Just a few miles away is the Gwaun Valley, a forgotten enclave where the tiny Duffryn Arms lays claim to be the least spoilt pub in Britain. Check out our guide to Lon Teifi for more, but be warned: you may never want to leave.

Laugharne (165mi) You don’t have to go into Laugharne – there’s an inland cut-off that saves you a few miles (and climbs). But if you’ve ever read any Dylan Thomas, or simply enjoy sitting by the sea with a pint, this artsy Georgian-styled town is a must-see.


Tenby (180mi) At 43 miles, Carmarthen to Pembroke is doable in a day: but we’d strongly counsel that you take it easier, perhaps stopping at Tenby after 32 miles. Tenby’s colourful houses and inviting beach give it the air of a resort town, yet this is hardly candyfloss and amusement-arcade country: your camera will be clicking away to capture the harbour views. The five miles here from Amroth are particularly enjoyable, as the route dives onto the coast path to tunnel under cliffs and cross beaches.

Pembroke (191mi) Pembroke’s narrow main street has an olde-worlde air, descending to the splendid castle at sea level – of which the Celtic Trail gives excellent views. Pembroke Dock, two miles on, is an entirely separate and more workaday town. The Milford Haven Waterway splits and splits again into the inlets on which these settlements thrived; today, the cyclist endures a windy haul across the estuary bridge to reach one of the jewels of the Celtic Trail.

Johnston (200mi) The ‘Brunel Cycle Trail’ takes up the route from here to Johnston, three miles on. Short it may be, but this beautiful, smoothly-surfaced little route is what rural cycle paths should be. Its Brunel ancestry is apparent as it pulls up close to the railway at its terminus: he’d make a great cycle path engineer.

Broad Haven (209mi) Skirting the edge of Haverfordwest, the Celtic Trail heads for the Pembrokeshire coast at Broad Haven and the most undulating part of the route. Believe us, you’ll feel every valley in the pedals, but the coastal views make up for it – mostly. The signs head inland at Roch, but if the traffic’s light, you could follow the coastal A-road via the cherished seaside villages of Newgale and Solva.

St David's (224mi) St David’s is famously the smallest city in Britain. Anywhere else it would be a village – were it not for the small matter of the cathedral. Tourists give it a good range of pubs, cafés and B&Bs, and there’s an out-of-town youth hostel for budget accommodation.

The last 17 miles to Fishguard cling to the coast once again, but it’s a little less exhausting than the Broad Haven section. A relaxed schedule will give you time to stop in famously pretty seaside villages like Porthgain (just off the route) and Trefin; thousands are drawn to walk the Pembrokeshire Coast Path every year, and it would be a shame not to share the coastal experience.

Fishguard (243mi) One final climb takes you over the hill to Fishguard, where buzzards circle above the busy roads for the final run-in. Down by the sea, you’ll find the Ocean Laboratory, the harbour for ferries to Rosslare, and a brand new railway station at Fishguard & Goodwick. Climb the hill, and you’ll arrive at a busy little town where we’d suggest a visit to the museum and to the Fishguard Arms pub. It’s easy to catch the train back from here. But the high-level route over the hills back to Carmarthen is surely a tempting alternative…