Greystones signed a Twinning Oath with Holyhead in Wales in 2012, based on both towns having similar populations, maritime traditions, and community clubs and activities.
A number of groups and individuals have visited Greystones from Holyhead and return visits have also taken place. Representatives from Holyhead Sea Cadets, Holyhead Round Table, Maritime Museum and Holyhead Hotspurs FC are regular participants in the annual St. Patrick's Day Parade in Greystones.
The boat 'Becky IV' was the first boat from Holyhead to sail into the new harbour in Greystones and has been a regular visitor since then. Many personal contacts have been established with visitors from Greystones attending the Old Gaffers Traditional Sailing Festival in Holyhead each August.