- 2000-00-00 Guitarist TAKE forms unknown prototype band in Tokyo (東京).
- 2002-04-00 Unknown prototype band disbands.
- 2002-07-00 Guitarist TAKE, vocalist Hiro, and guitarist miya form PHOTOSPHERE (フォトスフィア).
- 2002-08-00 PHOTOSPHERE (フォトスフィア) holds first live.
- 2003-08-00 TAKE opens bar.
- 2003-10-00 Bassist C'La joins.
- 2003-10-00 PHOTOSPHERE (フォトスフィア) changes name to Regret.
- 2003-11-23 Feels a dear wind released.
- 2004-01-00 Guitarist miya secedes.
- 2004-02-00 MAO joins as support drummer.
- 2004-04-26 Grows away released.
- 2004-05-00 According to the band's official history, they “meet” guitarist itsuki and drummer gutti. I've never heard of gutti again, so I can only assume that he did a one-off live as support drummer. itsuki wasn't mentioned in the band's August 2004 flyer, so I'm guess he didn't actually join the band until their September sponsored event.
- 2004-08-00 For some reason, itsuki is absent from an August 2004 flyer. However, he was posting in the band blog as late as December that year, and was mentioned as a member when the band announced their activity pause. So, I'm not sure if he temporarily left the band around this time.
- 2004-09-29 First free oneman is held at Akasaka (赤坂) L@N. Guitarist itsuki joins(?).
- 2004-09-29 Beautiful Dancing c/w.HIGH SPIRITS released.
- 2004-10-00 Bassist C'La secedes(?). (Not sure of the date: he's on an August 2004 flyer, but is not listed as a member on the band's website in October of 2004. However, he and C'La joined 響~hiViki~ in November 2004.)
- 2004-10-00 Former guitarist miya re-joins as bassist.
- 2004-11-27 「Uwasa」 c/w.Imademo Bokura ha released.
- 2004-12-25 First sponsored event is held at Akasaka (赤坂) L@N. An unknown CD is freely distributed to the first 20 attendees.
- 2004-12-25 (unknown title) released.
- 2005-01-27 Unofficial last live is held.
- 2005-01-27 Regret pauses activities
Regret holds one-day revival at
CindyKate-sponsored Otake (おたけ) birthday event, Genten Kaiki! Otake BIRTHDAY~Regret Fukkatsu~ (原点回帰!おたけBIRTHDAY~Regret復活~), at Kagurazawa (神楽坂) EXPLOSION.
- 2013-06-15 Regret disbands
- 2013-06-15 Regret Special Album released.