Mogg will reunite with former Brumbies coach Jake White and captain Ben Mowen in the south of France after turning down a three-year offer to stay in Canberra.

News of Mogg's departure at the end of the year has been offset by Robbie Coleman's decision to re-sign with the Brumbies for at least another two seasons.

Coleman has turned down the chance to chase a potential Olympic Games gold medal with the Australian sevens team to extend his stint at the Brumbies.

It's understood the Canberra Raiders also tried to poach Coleman, but the Queanbeyan junior and former rugby league teammate of Josh Dugan never seriously considered the NRL offer.

Coleman looms as the long-term fullback option with Mogg joining Nic White in deciding to link with White in France at the end of the year.

Mogg told his Brumbies teammates of his decision on Wednesday night Australian time and he will start a two-year contract, with an option of a third season, at the end of the year.

White tabled a massive offer to Mogg two weeks ago that was too good to refuse, believed to be worth double what the Brumbies could come up with.

"I chopped and changed on a decision for a while. At the end of last year I thought I'd go overseas, but then I had shoulder surgery so my aims changed," Mogg said.

"I wanted to give the Wallabies another crack. I thought I was going to stay and over the last couple of weeks is where it changed.

"I am happy with the decision I made, things were moving along slowly with the Brumbies and part [of the decision] was security."

The Brumbies were desperate to keep Mogg and his booming left boot in the capital for at least the next three years as they aim to build a sustainable squad.

White is building a Brumbies revolution at Montpellier, with Mowen already established and Mogg and Nic White to partner in France.

Mogg has played just a handful of games this season after recovering from shoulder surgery.

"With only five games left and having not played, it was hard to push my case for a contract at any club," Mogg said.

"I spoke to Jake and I had to make a decision, I didn't want it to linger on. I made the decision, I don't regret it. I'm content and happy with it.

"It was more of a security thing, negotiations had been going for a few months with the Brumbies and we couldn't come to an agreement we both loved."

Jake White plucked Mogg out of Canberra club rugby at the end of 2011 to kickstart his professional career.

Mogg's selection from obscurity proved a masterstroke as the 25-year-old made his Wallabies debut against the British and Irish Lions in 2013.

"It's obviously going to be easier with Jake being the coach, he knows how I work and I know how he works," Mogg said.

"I'm looking forward to it and I'm happy with my decision. I wasn't going around to other clubs and looking for contracts, but I spoke to Jake and he said he'd see what he could do if I was serious."

The Brumbies' re-signed utlity back James Dargaville earlier this week and have Coleman for the next two seasons.

Coleman had been flirting with a switch to Australian sevens to chase an Olympic dream, but wants to build a Super Rugby career.

One of the big factors in Mogg's decision to leave Australian rugby was knowing that Israel Folau stood in his way as the Wallabies fullback.

"Izzy has that locked down. Could I break into the team on the wing? Probably not," Mogg said.

"Maybe something on the bench? That's fairly slim. I didn't want to stay and not play [for Australia]. My intentions were to get back into the Test team. It was just a long shot.

"In terms of my Wallabies aspirations, it's a long shot for the World Cup."

Mogg hasn't ruled out a return to the Brumbies in the future.

"I'm only 25, if I want to come back I always can. One of the big decisions I had to make was could I go to another Super Rugby club and the answer was I couldn't see myself playing against the Brumbies."

SUPER RUGBY ROUND 13

Sunday: Cape Town Stormers v ACT Brumbies at Newlands, 1.05am. TV time: Live on Fox Sports 2