Trethias Island
Trethias Island is situated on the left side of Treyarnon beach. The island is separated from the headland by a deep gully which is filled with water except at low tide. At the seaward end of the gully there is an opening on the left-hand side which leads into a large cave which passes through the headland and emerges in the cove adjacent to Treyarnon.
Mentioned in walks
- Constantine Bay to Porthcothan (4.9 mile walk)
- Seven Bays (via bus) (6.8 mile walk)
Get the iWalkCornwall app
Download the app and use it to explore the walks and to purchase a guided route.
The app will direct you to the start of the walk via satnav.
The app guides you around the walk using GPS, removing any worries about getting lost.
The walk route is described with detailed, regularly-updated, hand-written directions.
Each time there is a new direction to follow, the app will beep to remind you, and will warn you if you go off-route.
A map shows the route, where you are at all times and even which way you are facing.
Each walk is packed with information about the history and nature along the route, from over a decade of research than spans more than 3,000 topics.
Once a walk is downloaded, the app doesn't need a phone or wifi signal during the walk.
The app counts down distance to the next direction and estimates time remaining based on your personal walking speed.
We keep the directions continually updated for changes to the paths/landmarks - the price for a walk includes ongoing free updates.
