In 2008 Shaun joined former Wasps colleague Warren Gatland as Defence Coach for the Welsh national side. Wales have since won Grand Slams in 2008 and 2012 as well as finishing fourth in the 2011 Rugby World Cup. In 2009 he was also part of Ian McGeechan's British & Irish Lions coaching team for the tour of South Africa.
"I'm excited at the opportunity of being involved in a Premiership Club set up again. London Irish has some fantastic players who I am looking forward to working with," said Edwards.
"The squad has put in some great performances this season and have been unlucky not to come away with more wins. I want to work with the team to see how we can then turn those frustrating last minute defeats into victories."
Edwards will have a number of Welsh players to work with at London Irish, including the newly signed Ospreys back row man Tom Smith. Former Cardiff Blues scrum half Darren Allinson and Wales Under 20 outside half Steve Shingler are also at the Exiles, along with another former Under 20 cap, back row man Ed Siggery and Wales cap Jonathan Spratt.
"Shaun is a world-class coach and he has been responsible for introducing a defensive system that has changed the shape of the modern game, consistently producing water tight defences in the Premiership, Six Nations, Lions' tours and Rugby World Cups," said Smith.
"He is a tough, hard-nosed coach, who I am confident will, alongside me, help to bring out the very best in the London Irish squad.
"We will have a strategy in place for next season to slash the numbers of points we concede in the Aviva Premiership. If we can do that then, this time next year, we can be a top four team and two games away from silverware."