FCDO advice including information on permitted duration of stay and visas for Ireland: https://www.gov.uk/foreign-travel-advice/ireland
For information on the validity of RYA certificates abroad see Evidence of Competence Abroad.
There is no specific requirement for evidence of competence other than that stipulated by the vessel's flag state.
A valid ICC should be acceptable evidence of competence as Resolution 40 has been formally adopted by Ireland.
We have been informed by Irish Sailing that following a review by the Marine Surveyors Office in the Department of Transport RYA Certificates of Competency, along with certain other UK issued ancillary certifications, are no longer valid for Commercial Endorsement in Ireland effective 1/1/21. Further information is available on the Irish Sailing website.
EU member state (part of the customs territory of the EU (which includes territorial waters)). Further information is provided on the Entry & Exit Formalities page under Customs - EU Member States.
Not part of the Schengen area.
There is a Common Travel Area (CTA) between, the UK, Crown Dependencies and Ireland under which British and Irish citizens can move freely – please see https://www.gov.uk/government/publications/common-travel-area-guidance/common-travel-area-guidance. See how the CTA has been affected by the coronavirus pandemic - https://www.gov.uk/coronavirus.
The law regarding the use of Marked Gas Oil (MGO) for private pleasure navigation changed on 1 January 2020. The use of MGO for private pleasure navigation is now prohibited and private pleasure craft owners should only purchase and use auto diesel as fuel for private pleasure navigation. See Red Diesel Abroad for further information.
Code of Practice for the Safe Operation of Recreational Craft - https://www.gov.ie/en/publication/66ff7e-safe-operation-of-recreational-craft/
Relevant Notices to Mariners tend to be posted in the news section of Irish Sailing’s website - https://www.sailing.ie/