Uk/irish resident paying CGT

If I’m classed as an Irish resident for current tax year & need to pay CGT on uk property, do I declare it in uk then Ireland aswell?

Hi,
Yes, you do. There is a calculator to help you work out the gain here:  
Tax when you sell property
You can register for an online capital gains account here:
Report and pay your Capital Gains Tax
If you cannot access the internet service, please contact our Income Tax team for advice and ask for a paper form.  
Income Tax: general enquiries
You will also be required to declare this disposal in Ireland and claim a foreign tax credit for the UK tax paid under the tax treaty.
Thank you.