A: There are two payment deadlines. CGT on gains made between 1st January and 30th November 2015 should have been paid by the 15th December 2015 whilst CGT on gains in December is due to be paid by the 31st January 2016. So, in your case you will need to pay your liability by the end of the month.
You will also have to file a CGT return with the Revenue Commissioners however this is not due straight away, you have until 31st of October 2016 (i.e.the year following when the gain was made). You asked could you wait to pay until filing the return. If you do this, a late fee surcharge will apply of up to 10% of the liability. Interest may also be applied by Revenue on a daily basis, backdated to the original payment date i.e. the end of January so it is in your interest to pay the liability sooner rather than later.
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