2019–2021: Kangin's departure, Time Slip, Super Show 8, 15th anniversary, Star and The Renaissance
On May 7, 2019, Kyuhyun fulfilled his mandatory enlistment, marking the end of Super Junior's military services. On July 11, Kangin voluntarily left Super Junior, although he will maintain his contract with SM and Label SJ. On July 12, 2019, Super Junior brought their Super Show 7S world tour to King Abdullah Sports City as part of the Jeddah Season festival, becoming the first Asian and K-Pop act to hold a solo concert in Saudi Arabia. The sub-units Super Junior-K.R.Y. and Super Junior-D&E also perform in the festival on July 13.
The nine-member lineup of Super Junior released their ninth studio album, Time Slip, on October 14, 2019, with Sungmin to have personal activities outside the group in the meantime. They temporarily halted performances and promotion due to the death of labelmate Sulli. The album is supported by four pre-release singles, "Show", "Somebody New", "The Crown", and "I Think I", and lead single "Super Clap". On October 12, the group embarked on their eighth tour ahead of their album release, Super Show 8: Infinite Time, starting in Seoul, South Korea. On October 20, Super Junior resumed their activities by appearing on Inkigayo to perform their lead single "Super Clap". However, Heechul did not participate with group due to his injury. The album also won first place in weekly music shows M Countdown and Music Bank. Time Slip received its platinum album certification on December 12, 2019.
They released their second Japanese mini-album, I Think U on January 29, 2020, which quickly rose to number one on Oricon Daily Albums Chart. In May 2020, it was announced that Super Junior would headline a live online concert – the sixth concert jointly organised by SM Entertainment and Naver as part of the world first high-tech online-dedicated live concert series Beyond Live. This was Super Junior's first concert after the cancellation of several Super Show 8 concerts in 2020 in Japan and other countries due to the impact of the COVID-19 pandemic, and was organized as part of a project of activities in 2020 to celebrate 15 years since the debut of the group. The live concert was held on May 31 and Super Junior played live to an audience of over 123,000 around the world. The concert revenue was estimated to be over 60 billion won. When finished, the main concert video as well as individual member cameras received a total of 2.8 billion hearts on Vlive, the highest record to date out of six concerts within Beyond Live series. During the concert, the hashtag #SUPERJUNIOR_BeyondLIVE' trended first in 13 countries and territories around the world spread across Asia, South America and the Middle East. During the concert, Super Junior played songs by the group and its sub-units. The concert also marked the first stage performance of "Home", the new unreleased track by sub-unit Super Junior K.R.Y from their first Korean album since debut of the sub-unit in 2006, which was released on June 8, 2020.
Super Junior was scheduled to release their tenth studio album, The Renaissance, in December 2020. A pre-release single titled "The Melody" was released on November 6, 2020, to celebrate the group's 15th anniversary. In the same month, the band signed with a US based talent and literacy agency, ICM Partners to represent them in other regions beside Asia. On December 10, it was announced that the release of their album would be delayed to January 2021 in order to improve the album's quality. Meanwhile, Super Junior unveiled a new unreleased single from their album during 2020's The Fact Music Awards on December 12. On January 8, it was announced that the album's new release date would be February 16. However, on February 1, it was announced that the album's release date was pushed back again to March 16.
On the other hand, the band also released a Japanese compilation album on January 27, 2021, in celebration of their 15th anniversary. The album, Star was released under their Japanese label Avex Trax and only featured two new tracks, "Star" and "Coming Home". The album was well received, peaking at number 3 on Oricon Daily Albums Chart on the day of its release, and at number 5 on Oricon Weekly Albums Chart.