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Visitor Notice

This monument is open and free to visit with no pre-booking required.

Check our opening times and facilities below; please act responsibly and be respectful of the local area during your visit.

Please adhere to Welsh Government social distancing guidelines and coronavirus restrictions at all times and do not attempt to access enclosed spaces.


Northern military outpost in a strategic coastal location

Dating back to the 3rd century, Caer Gybi’s position on low cliffs overlooking the sea suggests it was part of a coastal network of defences, possibly linked to the late Roman watchtower at Caer y Twr on the summit of Holyhead Mountain.

The walls of this rectangular fort are extremely well-preserved, standing up to 13ft/4m high and 5ft/1.5m thick. You can also see remains of four corner towers. Occupying a vantage point above the harbour, the 26ft/7.9m north-east tower is the most prominent, though the top section is a later rebuild possibly dating to the medieval period.

Opening times

Daily 10am–4pm

Last admission 30 minutes before closing

Closed 24, 25, 26 December and 1 January


Category Price


Dogs welcome icon No drones icon No smoking icon


In Holyhead, overlooking the harbour, off A5

For further information, please contact: Traveline Cymru on 0800 464 0000 or National Rail Enquiries on 03457 48 49 50.