CGT payment and CG1 filing happen at different times
In Ireland, you generally pay capital gains tax by 15 December for disposals from January to November, and by 31 January for December disposals. You file the CG1 return for that year separately, by 31 October of the following year. Paying is not filing.
Most people expect to calculate the tax and file a return in one go, the way income tax often works. Capital gains tax in Ireland does not work like that.
You pay first. For disposals between 1 January and 30 November, the tax is generally due by 15 December of the same year. For disposals in December, it is generally due by 31 January of the following year.
You file later. The CG1 return covering those disposals is due by 31 October of the year after you sold. A return is required even if no tax is due.
Because payment comes first and filing comes later, it is easy to pay and assume you are finished. You are not, until you file the return.
Written by The CG1 Assist team.
Published 20 July 2026. Last reviewed 21 October 2026.