The group - who were left stunned when their 33-year-old bandmate died last October - are to play 12 UK concerts early next year in support of their current album 'Brother', despite previously admitting they were unsure if they could play again without Stephen.
Singer Ronan Keating said: "There was a time when the lads and I didn't know whether we would ever get back up on stage together again.
"We just didn't know whether we could do it as a four-piece. We played three tracks live at the Royal Albert Hall a couple of weeks ago and the reception was just unbelievable. We all came off stage buzzing, knowing that we had the full support of the fans, and it all just suddenly felt so right. We can't wait to get back on the road together."
The tour starts on February 21, 2011, at the Liverpool Echo Arena, taking in a further 11 cities, including two dates in London.
Boyzone's 'Brother' tour dates:
February 21, 2011 - Liverpool Echo Arena
February 22, 2011 - Cardiff CIA
February 26, 2011 - London Barclaycard Wembley Arena
February 27, 2011 - Sheffield Arena
March 1, 2011 - Newcastle Metro Radio Arena
March 2, 2011 - Birmingham LG Arena
March 3, 2011 - Nottingham Trent FM Arena
March 5, 2011 - Manchester MEN Arena
March 6, 2011 - Brighton Centre
March 8, 2011 - London O2 Arena
March 10, 2011 - Aberdeen ECC
March 12, 2011 - Glasgow SECC