A Wedding on a Sunday is not forbidden by canon law, but is a matter for the local bishop to decide. A bishop can allow Sunday weddings within his diocese but generally it is forbidden in most Irish dioceses, because: *1. liturgically, the Sunday texts have precedence, and *2. it's burdensome for the clergy, who have extra parish duties on a Sunday.

The regulation in Dublin: "No marriage may be celebrated on a Sunday or Holy Day without the Archbishop's permission." (Pastoral Directives, 1982). For a substantial reason a bishop may dispense with this regulation. But it is hardly ever granted, so as not to set a precedent.