Hello! Project 20th Anniversary!! Hello! Project COUNTDOWN PARTY 2018 ~GOOD BYE & HELLO!~ was Hello! Project’s special annual countdown live concert to celebrate the new year. It took place on December 31, 2018 at Nakano Sun Plaza.
The countdown concert was split into two parts. The first part of the concert starting at 16:00 featured all Hello! Project members, while the second part starting at 23:00 only featured members over the age of 18.
The DVD and Blu-ray of the concert were released on May 15, 2019.