In most dioceses, the day after a priest is ordained (or soon after), he celebrates the first Mass where he is the main celebrant. He may also celebrate one or more “Masses of Thanksgiving” in churches or chapels of particular significance to him (for example, the chapel of his college campus ministry).
These Masses are normally open to anyone to attend to give thanks for the new priest, to pray for his fidelity in his vocation, as well as to gain a plenary indulgence, if all the usual conditions are met. (Learn more about plenary indulgences here.)
More details will follow for 2023.
First Masses of the priests are scheduled for Sunday June 4.
The new deacons will also have the first Mass when they serve as a deacon and preach the homily. Those are on Sunday, April 16.