A lot of Northern Irish trades work south of the border without ever thinking of it as international. The van crosses, the job is in Donegal or Monaghan or Dublin, and the money comes back. But CIS stops at the border. What is waiting on the other side is Relevant Contracts Tax, and if you are not registered with Irish Revenue it takes 35%.
Relevant Contracts Tax is the Republic's withholding scheme for construction, forestry and meat processing. It does the same job as CIS and it is not CIS: different rates, a different revenue authority, a different way of setting your rate and a different way of getting the money back.
Revenue are explicit that it reaches you even though you are not resident there. Their guidance for non-resident subcontractors says that if the work is being carried out in Ireland a principal contractor should deduct RCT from your gross payment, and that this is the case even if the principal is non-resident too. Being a Northern Irish business on a Northern Irish payroll makes no difference at all.
RCT runs at 0%, 20% or 35%, and the rate follows your compliance record with Irish Revenue. An up-to-date record is 0%. A substantially up-to-date record is 20%. A poor record or not being registered with Revenue at all is 35%. That last clause is the one that catches people: turn up to a job in the Republic without an Irish tax registration and you are on the top rate from the first payment, not because anything is wrong with you but because Revenue have never heard of you.
The mechanics are the principal contractor's job rather than yours, but you cannot get paid properly if you do not know what they are doing:
Revenue run rolling Bulk Rate Reviews that reassess every subcontractor's compliance position and can move your rate without you doing anything. The notice goes to your ROS inbox. If you never log in, the first you know about going from 0% to 20% is a short payment. Once the underlying issue is cleared you can self-review your rate in ROS, but allow at least 72 hours after fixing it before you do.
Where RCT applies to a service, Irish VAT goes to the principal rather than to you. Revenue put it plainly: the principal contractor accounts for the VAT to Revenue directly, as if they had supplied the service themselves. It is a reverse charge, and it applies to construction subcontractors only.
The consequence is the useful bit. Revenue state that non-resident subcontractors providing construction services to principal contractors are not required to register for Irish VAT. You may still want to, in order to reclaim Irish VAT you have paid on materials, plant hire or diesel bought down there — but that is a choice about recovering money, not an obligation you are breaching by ignoring.
RCT deducted from you is recovered from Revenue, not from HMRC, and it is a separate exercise from your UK tax return. The forms are IC1 if you are an individual and IC3 if you trade through a company, with an RCT questionnaire for each contract and a copy of the deduction authorisation. They are handled by Revenue's International Claims Section in Nenagh.
⚠️ The timing trap: the tax authority of your country of residence has to certify the IC1 or IC3, and they must certify it in the year the income was earned. Leaving the whole thing until you do your Self Assessment is how people end up unable to get the certification they need.
None of this takes you out of the UK system. You are still a UK business with UK accounts and a UK tax return, the Irish work is still your turnover, and the profit on it is still taxed here. What changes is that some of your cash is sitting with Revenue rather than with HMRC, and that relief for the Irish tax has to be handled properly rather than assumed. Get that wrong in either direction and you either pay twice or you claim something you are not entitled to.
We are a UK practice. We are not registered as a tax agent in the Republic and we do not file Irish returns, so this page is here to tell you what happens and what to get right rather than to sell you Irish compliance. What we do is the UK side — your CIS, your VAT, your accounts and your tax return — with the Irish deductions and the Irish VAT treatment carried through it properly. Where you genuinely need an agent in the Republic we will say so rather than improvise.
We have an office at Unit 13:62 Fenaghy Road, Ballymena, Co. Antrim, BT42 1FL, and Northern Ireland is our largest base. You can come in and sit down with somebody by appointment, or do the whole thing by phone, video and WhatsApp like most people do. 07476 989568.
If some of your work is in the Republic, say so at the start and we will set the bookkeeping up to keep the two apart from day one. It is considerably easier than separating them afterwards from a year of bank statements.
No. CIS is a UK scheme and it applies to construction operations carried out in the United Kingdom. Work carried out in the Republic falls under Relevant Contracts Tax, which is Irish Revenue's equivalent withholding scheme. The rates are 0%, 20% and 35% rather than 20% and 30%, the rate is set by your compliance record with Revenue rather than by verification with HMRC, and the money is reclaimed from Revenue rather than through your Self Assessment return. If your work straddles the border you are in both schemes at once, on different jobs, and the bookkeeping needs to keep them apart.
Because 35% is the rate Revenue apply to a subcontractor with a poor compliance record or to one who has not registered with Revenue at all. For a Northern Irish trade turning up to a first job in the Republic it is almost always the second. You are not in trouble, you are simply unknown to them. Registering for Irish tax and for ROS, and getting a deduction rate determined, is what moves you off it. It is worth doing before the job rather than after, because the deduction comes off the payment and the money then has to be reclaimed.
Not for construction services supplied to a principal contractor. Where RCT applies, the Irish VAT reverse charge puts the VAT on the principal, who accounts for it to Revenue as if they had supplied the service. Revenue state directly that non-resident subcontractors providing construction services to principal contractors are not required to register for VAT. You may choose to register anyway so you can reclaim Irish VAT you have paid on materials, plant hire or fuel bought in the Republic, and if you spend much down there that is often worth doing.
Through Irish Revenue, not HMRC. An individual uses Form IC1 and a company uses Form IC3, with an RCT questionnaire for each contract and a copy of the deduction authorisation the principal gave you. The claims go to the International Claims Section in Nenagh. The part people miss is that your own tax authority has to certify the form, and has to do it in the year the income was earned, so this is not something to leave until you are doing your UK return eighteen months later.
A SIN is the number Revenue issue to the principal contractor when they notify a contract, and it identifies the site or project rather than the person. Revenue tell you what it is in your contract confirmation letter. If you then subcontract part of your own work you use the same SIN when you notify that contract, so every contract by every contractor on one site carries the same identifier. There is no CIS equivalent, which is why it catches people coming from the UK scheme.