Social security coordination rules protect the rights of citizens should they move between the jurisdictions for work.  The rules establish which jurisdiction is responsible for the person; where they’ll pay compulsory social insurance contributions and where they’ll claim contribution based benefits.  They will only contribute to one system at a time.

The jurisdiction responsible for social security payments is often called the Competent State and is usually the place of employment or self-employment.

Social insurance contributions are referred to as Pay Related Social Insurance (PRSI) in Ireland and National Insurance Contributions (NICs) in NI. They are usually collected through the employer’s payroll and the worker will only pay into one social insurance system at a time.

Example – full time commuting

• Live North, Work South 5 days per week = the responsible state will be Ireland and the worker will pay PRSI.
• Live South, Work North 5 days per week = the responsible state will be NI and the worker will pay National Insurance Contributions.

Example – hybrid working

Working from home more than 25% of the time*, carrying out work duties in the jurisdiction of residence, or working in both jurisdictions could change the Competent State to where the person lives.

• Work from home North 2 days per week
• Commute South 3 days per week
• The responsible state will be NI and the person will pay National Insurance Contributions.

The coordination rules state that a person is only liable in one jurisdiction at a time.

Example – working for different employers in both jurisdictions

• Live North, Work North – 2 days per week for employer 1
• Live North, Work South – 3 days per week for employer 2
• The responsible state will be NI and the worker will pay National Insurance Contributions on both employments!  Employer 2 will need to set up a special payment to HMRC.

Proof of Competent State

If the situation is unclear, the worker or their employer can ask the Irish or UK authorities to confirm which jurisdiction is responsible and a Certificate of Coverage (PDA1) will be issued. This is especially useful if the worker is employed in both jurisdictions as it states exactly which system the person is linked to.

Social Insurance Record

As workers pay social insurance contributions they build up a record which can be relied upon in event that a social welfare payment is needed (e.g. illness benefit).  Any social security payments that are linked to social insurance contributions are usually exportable across the border.  PRSI contributions can be combined with National Insurance Contributions to help a person qualify for a contribution-based payment.

Please note that State Pension entitlement will not arise when contributions have been incorrectly paid.  If a mistake is made and a person pays both PRSI and National Insurance at the same time refunds can sometimes be requested but they are time limited. A citizens information advisor can guide you in this circumstances.**

Voluntary contributions

In limited circumstances workers can choose to pay voluntary social insurance contributions, please see the following page for further information – Border People – voluntary contributions

Exporting benefits

The coordination rules list the benefits that can be exported by each country, the benefits are listed by category e.g. sickness payments, long term care benefits, old age benefits, family benefits, etc.  The rules prevent a person claiming the same type of benefit from both jurisdictions (there are only a few exceptions e.g. state pensions).

Sickness benefit example:

• Living North, Working South 5 days per week = the responsible state will be Ireland, the worker will pay PRSI and will claim Irish Illness Benefit if they are too ill to go to work.
• Living South, Working North 5 days per week = the responsible state will be NI, the worker will pay National Insurance and will claim UK Employment and Support Allowance if they are too ill to go to work.

Sources:

• Gov.uk – Paying National Insurance if you’re going to work in the EU
• Border People – Voluntary Social Insurance Contributions
• Border People – Comparable UK and Irish benefits in cash
• EU Coordination Rules 
• UK Ireland Social Security Convention
• Trade and Cooperation Agreement

*Note that the 25% rule is commonly used, but other factors may also be taken into consideration. See Article 14 of Regulation (EC) No 987/2009 laying down the procedure for implementing Regulation (EC) No 883/2004 on the coordination of social security systems (see Articles 12 and 13).  The EU rules apply to pre-Brexit cross-border workers, for Irish and British workers who took up employment from 1st January 2021 onwards the UK Ireland Social Security Convention applies. It preserves the single state rule however it does not specifically state the 25% threshold, any use of that threshold is interpretative only not a statutory ruling.  Border People can provide further information on this to members of the Advice Sectors in Ireland and Northern Ireland.

** Refunds: In Ireland, sections 34 and 38A of the Social Welfare Consolidation Act 2005 generally require an application within four years from the end of the contribution year. In the United Kingdom, regulation 52 of the Social Security (Contributions) Regulations 2001 generally allows six years from the end of the relevant year, subject to an extension where there was a reasonable excuse and no unreasonable delay.

Page last checked: May 2026

Links last checked: 27th July 2026

This webpage is for general information purposes only and while we endeavour to keep it up-to-date, errors may occur. It is very important that you check with the relevant body to ensure the information is current and is applicable to your situation.

If you would like to suggest amendments or highlight new information that could be useful to others please don’t hesitate to get in touch.