The use of face coverings by all those attending indoor religious services if is strongly recommended. This means that non-wearing of face coverings should only occur in exceptions circumstances. In certain circumstances, (and this would include smaller Churches or places that are not well ventilated) the wearing of face coverings is obligatory by virtue of the general norms and is legally binding.
The Framework Document of the Irish Bishops and the HSE guidance say that face coverings are obligatory on priests, deacons and lay ministers for the distribution of Holy Communion.
Archbishop of Dublin