Tomonaga Mio is a member of HKT48's Team KIV and AKB48's Team4B.
- Joined HKT48 as a Research Student in September, 2012
- Promoted to Team KIV on January 11, 2014
- Had a Concurrent Position in AKB48's Team B since February 24, 2014
- Has a Concurrent Position in AKB48's Team 4 from March 26, 2015