Walk - Constantine Bay to Mawgan Porth

Walk information provided with help from Natural England. Map reproduced by permission of Ordnance Survey on behalf of HMSO. © Crown copyright and database right 2025. Ordnance Survey Licence number 100022021.
Route Description
If you are starting the walk by the golf course, follow the nearby footpath down to Constantine Beach first.
- From the beach car park at Constantine Bay head down the sandy path towards the beach. As you approach the beach, bear left on the South West Coast Path. Follow it around Treyarnon Point and on to the beach at Treyarnon Bay.
St Constantine was one of many Celtic missionaries working around Cornwall in the sixth century in response to the tide of paganism which had arrived in England with the Anglo-Saxons after the Romans had left. The remains of St Constantine's hermit cell and the associated well have been preserved in the nearby golf course. Also King of Dumnonia, St Constantine led such an unholy life in his early years that fellow Celtic saint Gilda called him an 'unclean whelp'. He was accused of disguising himself as a bishop and murdering his two young nephews in the sanctity of a church.
One day while he was out hunting, the deer he was chasing blundered into the cell of Padstow-based St Petroc. Following the creature in, Constantine got talking to St Petroc and was so impressed with the hermit's holiness that he had himself and his bodyguard converted on the spot to Christianity. Abdicating his throne in favour of his son, he became a missionary himself, founding churches at Falmouth and Illogan as well as the one in Constantine Bay.
- After crossing the stream at Treyarnon, pick up the Coast path once more on the far side of the beach, climbing gently up to round the point by Trethias Island and carry on between farmland and the dramatic cliffs.
At low tide a wonderful rock reef appears at the far end of Treyarnon Beach, riddled with rock pools, one of them large enough for swimming and all of them worth exploring. Trethias Island is separated from the mainland by a deep gully, and hides a huge cave which extends under the headland, emerging in the small cove beyond. (Note: The tide comes in very rapidly, cutting this area off from the main beach in minutes and flooding the cave. Take care if you choose to explore it).
On the headlands immediately above Trethias Island are three prehistoric cliff castles dating back to the Iron Age, sometime between 800 BC and AD 43. These primitive promontory forts took advantage of the cliffs to protect their communities on the seaward side, building earthwork ramparts on the landward side to give some protection from possible attacks. The remains of these ramparts can be seen under the grass along this part of the Coast Path.
The landowners are working with the RSPB here to protect the corn bunting, which appears on the international Red List of threatened species as a bird in danger of global extinction. Intensive farming operations in the past destroyed vital habitats and food sources. Traditional methods of land management are being used in many places around the south west coastline to restore the corn bunting population. Look out for them in the fields on your left, foraging for food or singing from the fence posts.
The Coast Path continues straight ahead past the series of headlands, but detouring on the smaller paths hugging the coastline gives an interesting view of the dramatic rock formations caused by the pounding of the waves.
The bedrock under this area is known as the Trevose Slate Formation. Consisting of slate and siltstone, it was formed in layers at the bottom of a deep ocean, way beyond any land, approximately 364 to 391 million years ago in the Devonian Period. There are deposits of fine material from microscopic sea organisms in the rock. Fossils of planktonic creatures found in the slate along this coastline have helped geologists date these rockbeds.
Breakers rolling in from the Atlantic crash relentlessly around the cliffs. They eat into the rock along fault lines, where it is weaker, turning cracks into caves and then washing around the caves to make them bigger. The pressure of the air forced through the cave causes a blowhole in the roof if it is close to the surface, and this is also enlarged, so that eventually the roof of the cave falls in. The sea continues its erosion, cutting off the outer wall from the coastline, forming first an arch and then an island. In its turn this is reduced to a stack, while the cave becomes a cove and finally a bay.
The cliffs are very unstable as a result of all this erosion, so take care around the headlands.
The inlets and coves made this an ideal coastline for smugglers, who supplemented their meagre livelihood from fishing with a spot of Free Trade. The rocky caves with their sandy floors made a perfect hiding place for the contraband. Padstow resident William Rawlings wrote to the Earl of Dartmouth in 1765, complaining that his servants had on one occasion encountered no fewer than 60 horses travelling up from one of these beaches ‘having each three bags of tea on them of 56 or 58lbs weight’.
- Ignore the path inland just before the open access land, carrying on to Porthcothan. There is a network of paths through the heathland here, but the Coast Path continues around the coastline, with more examples of the spectacular coastal erosion.
Please keep dogs on a lead along this part of the walk. There are often sheep grazing here - a conservation strategy employed by the National Trust to control the aggressive rank grasses and scrub that would otherwise smother the important maritime grasslands.
This cliff-top vegetation is particularly prized by conservation bodies because it is one of the most “natural” in the UK. The high salt content of the air this close to the sea discourages or kills the more vigorous, faster-growing land plants, leaving the way clear for the more delicate but salt-tolerant species to flourish. Unusual plant species here include the tree mallow, with its massive pink flowers, and the golden samphire, which looks like a handful of dwarf beans dotted with tiny yellow flowers. The rubbery leaves are edible, and are often added raw to salads or boiled and served with butter like asparagus. Rock sea lavender also thrives here, resembling heather with its lilac flowers, as does betony, whose purple heads are often humming with insects.
Note the traditional 'curzyway' stone walls along the way, also known as 'Jack and Jane' walling, where the slates have been stacked in a herringbone pattern before being populated by delicate lichens and stoneworts. Clumps of the pink-flowered thrift tumble over them like thatch, topped by fronds of tamarisk, a feathery-leaved Mediterranean plant which loves dry sandy soil.
- At Porthcothan turn right on the road and follow it around the back of the beach, picking up the Coast Path on the far side again. Climbing gently up the cliffs around the headland, cross the stream to continue to the cove at Porth Mear (Cornish for 'Great Cove'). Crossing another stream, carry on above the cliffs and headlands to turn left across Park Head and follow the edge of fields around Pentire Steps and past Diggory's Island.
Like many of the headlands on this part of the Cornish coastline, in the Iron Age the tip of Park Head was a promontory fort, or cliff castle. Around the headland the cliffs have slumped: take care not to venture too close to the edge.
- Carry on above the spectacular rocks and islands at Bedruthan Steps, passing the island at Pendarves Point to come to Whitestone Cove. At Carnewas Point the 'island' is still attached to the mainland by a narrow causeway of rock, visible at low tide. Carry on past the disused mineshaft at Trerathick Point, above two tiny coves far below, coming finally to Trenance Point, where the path pulls out around the top of the cliffs before descending gently towards the beach at Mawgan Porth. Stay with the Coast Path all the way to the road.
The beach at Carnewas at Bedruthan is inaccessible due to a significant rock fall damaging the stairway to the beach in 2019. No alternative route is currently available and visitors are advised not to find alternative routes onto the beach.
- At the road turn left to walk to the bus stop.
Although it is the spectacular shapes of the islands, stacks and arches that make Bedruthan Steps one of the Coast Path's most iconic views, it is a Site of Special Scientific Interest because of the fossils it contains from the Eifelian Age, almost 400 million years ago. Notable among these is the Pteroconus mirus, a large planktonic creature which swam in the open seas and is believed to have had bladders to help it float. Other fossils include bivalves, some underwater scavengers similar to trilobites, the flat discs of a stalked sea lily known as a crinoid, and a primitive jawless fish known as a pteraspis.
On the hillside above the beach at Mawgan Porth are the remains of a Saxon settlement dating from around AD 850-1050. When the site was excavated in the middle of the last century, archaeologists uncovered three courtyard house complexes. The walls were built of soft slate and earth and faced with stone, and each building had a long room opening into a courtyard bordered by smaller rooms. The long room was partitioned to accommodate livestock while still keeping the animals out of the central living area, which had a hearth, and cupboards in the walls.
Nearby refreshments
In Porthcothan and Mawgan Porth. The Merrymoor Inn in Mawgan Porth is recommended by users of www.doggiepubs.org.uk as serving good food and being dog-friendly.
