Tanpopo# released their first single under their new name in July 2009 on a Hello! Project compilation, a cover song called "Akai Sweet Pea". In December 2009, they released their second single, an original song called "Umbrella". Tanpopo# continued to be an active unit throughout 2010 and 2011, appearing in variety skits and touring in various Hello! Project concerts. Following Eri Kamei's graduation from Morning Musume and Hello! Project in December 2010, she effectively graduated from Tanpopo# as well. Yurina Kumai was appointed the new leader of Tanpopo# following Eri's graduation.
Tanpopo# ceased activities following the Hello! Project winter tour in 2011 along with five other revived units, unofficially confirming their disbandment.
On December 31st, 2016, Tanpopo# had a reunion with members Yurina Kumai and Okai Chisato (Aika Mitsui is on hiatus) and was joined by former second generation Tanpopo member Rika Ishikawa to perform "Koi wa Shichaimamashita!" at the Hello! Project Countdown ~Goodbye & Hello~ 2016 concert.