A couple can get married on the three days in between Yom Kippur and Sukkot. Holding a wedding on the day immediately before Sukkot is technically permitted, however Rabbi Abraham Gombiner (17th century Poland) writes that since the meal can easily encroach on the holiday festivities that night, it is not the custom to make a wedding on the day before Yom Tov, and this custom should not be changed.1

Rabbi Pinchas of Koretz (1726-1791) explains that, according to Kabbalah, this is a very good time to get married. He also tells of a man for whom several marriages ended in divorce. Upon being advised to marry during this auspicious period, he did so and lived with his wife and family happily for the rest of his life.2

Please see Choosing a Date for a complete guide to choosing the right day for your wedding as well as a comprehensive date list.

Yours truly,

Rabbi Eliezer Posner