Irish CGT deadlines: when you pay, and when you file

Two deadlines, not one

Most taxes in Ireland are settled once: you file a return and pay what the return says. Capital Gains Tax is not one of those. Revenue separates the two obligations completely, and they land in different calendar years.

Payment is due within weeks of the disposal, under a self-assessed estimate you make yourself — before any return exists, before Revenue has seen a single figure. The return is due on 31 October of the year after the disposal, which for a January disposal is nearly twenty-two months later.

Neither deadline substitutes for the other. Paying on time does not excuse a late return, and filing a return does not retrospectively fix a payment that was late. They carry different consequences — interest on one, a percentage surcharge on the other — which is covered further down.

The two payment periods

The Irish tax year for CGT is the calendar year, and Revenue splits it into two unequal payment periods. Which one a disposal falls into is decided purely by the date of disposal — not by when you were paid, not by when the trade settled, and not by when you worked the figure out.

The first period is eleven months long and the second is one. That asymmetry is deliberate: it gives Revenue the bulk of the year's CGT before the calendar year closes, while still leaving a workable window for December disposals, which would otherwise have a fifteen-day deadline.

What you are paying is an estimate you make yourself

CGT is self-assessed. On 15 December there is no form to complete and no assessment from Revenue to work from. You compute the gain, apply the 33% rate to whatever remains after losses and the €1,270 personal exemption, and pay that amount. The return filed the following October is where the figure is formally declared and reconciled.

That is the mechanical reason the two dates exist so far apart, and also why the arithmetic matters in December rather than in October. The Capital Gains Tax guide sets out how the gain itself is computed.

The return, filed the following year

Revenue states the filing rule plainly: you must file your CGT return on or before 31 October of the year that follows the date of disposal. A disposal on any date in 2025 — 3 January or 29 December — is reported on a return due 31 October 2026.

Which return

The form depends on what else you file, not on the size of the gain:

A single return covers the whole tax year, both payment periods together. There is no separate December return.

The ROS extension, and what it does not cover

Revenue publishes an extended pay-and-file date each year for people who both pay and file through ROS. For the 2025 income tax return the extended date is 18 November 2026, against the statutory 31 October 2026. The extension is conditional: if you file through ROS but pay by another route, or pay through ROS but file on paper, the ordinary 31 October date applies.

What is live right now

As of August 2026, the return currently open is the one for the 2025 tax year. Anyone filing a CGT return this autumn is reporting disposals made between 1 January and 31 December 2025 — disposals whose tax was already payable in December 2025 or January 2026.

Note the overlap. In the same autumn you are reporting one year and paying for another, from two different sets of disposals. Keeping the two sets apart is the single most useful habit in the whole arrangement.

Three worked timelines

The same rules, traced through three disposals that fall in three different places in the calendar. Figures are illustrative and rounded to the cent.

A disposal in March

A disposal in December

Both, in the same year

If both disposals above had been made by the same person in 2025, the exemption would not apply twice. It is a single €1,270 per individual per tax year, set against the year's net gains — but the tax still has to be split across two payment dates, because the payment obligation follows each disposal separately.

Funds and ETFs run on a different clock

The 15 December and 31 January dates belong to Capital Gains Tax. Gains on Irish and EU-domiciled funds — most ETFs an Irish investor holds — are not charged to CGT at all. They fall under the investment undertaking and offshore fund regimes, which are self-assessed through the Form 11 and paid at the same time as the return, on 31 October of the following year.

A portfolio holding both therefore has three payment dates in play for a single tax year, not two. The ETF tax guide covers which regime a given fund sits in and how the rate is determined by the date of disposal.

Returns where no tax is due

A common assumption is that a year with no CGT bill needs no return. Revenue's position is the opposite: where you have disposed of an asset, a return is required — and Revenue states it explicitly, that you must file “even if no tax is due because of reliefs or allowable losses”.

Three situations where this catches people:

• The gain fell under the exemption. A €1,270 gain produces no tax, but the disposal still happened.
• The year was a loss. A loss you never return is a loss Revenue has no record of. Carrying it forward against a future gain depends on it having been declared.
• Losses wiped out the gains. The net position is nil, but the disposals and the losses both need to appear.

Interest and surcharges

The two obligations fail in different ways, and it is worth knowing which is which before assuming a single penalty covers both.

The surcharge is a percentage of the tax, not a flat fee, so on a large gain a return filed two months and one day late is an expensive document. It is also charged on the liability as computed, which is why a late return following an accurate December payment still costs something.

How the payment is actually made

Payment is made online, through ROS if you are a self-assessed filer or through myAccount otherwise. Revenue requires you to be registered for CGT before paying: if you are not already registered, that registration is the first step and it is done through the same services.

• You need your PPSN, the tax year the payment relates to, and which of the two periods the disposal fell into.
• The payment is tagged to a period. A December disposal paid against the initial period is a payment sitting in the wrong place, even though the money arrived.
• Keep the working behind the figure. The return is filed months later, and the number you pay in December is the number the return has to reconcile to.

Vantanomic groups your disposals by payment period and shows the estimated tax for each, which is the arithmetic that has to be done before the December date rather than after it.