Confession Not Obligatory During Advent

No. But when you have sins to confess, any time is a good time for confession. Catholics are bound by an obligation to confess serious sins at least once a year (CCC 1457). Traditionally, the Church encourages the faithful to confess their sins annually during Lent and Easter (CCC 2042). Although Advent does have a penitential aspect to it, it’s not a true penitential season, which is why it doesn’t make the list of penitential days and times in the Church (Code of Canon Law, can. 1250)