It is a widely accepted custom for all men to immerse in a mikvah (ritual pool) on the day before Yom Kippur. In certain communities, women also immerse in a mikvah on this day.

There are two reasons for this immersion:

  1. In order to be ritually pure in preparation for the holiest day of the year.
  2. The immersion is symbolic of conversion. Just as a convert immerses in a mikvah and thus becomes a "new person," so, too, it is our intention to do teshuvah (repentance) and become new people.