The 26-year-old will join Leicester "with a heavy heart" after missing out on the "dream" finish to his time in Super Rugby.

With a raft of stars leaving, the Brumbies had hoped to break their 12-year title drought in 2016.

Instead, their season ended on a controversial note with inconclusive video footage leading to a no-try decision when in all likelihood Lausii Taliauli had scored what could have been the match winner.

He said everyone on the field, including the Otago Highlanders, felt it was a try, but he didn't want to use that as an excuse for the loss – they just weren't good enough.

Toomua arrived in Canberra as a teenager in 2007 and the Brumbies became his family.

He made his Super Rugby debut the following year at a time when the Brumbies were a mid-table team.

It took five seasons before he'd play his first final, but they've made the grand final, two semis and a qualifying final over the last four years.

Toomua was thankful to the Canberra community and hoped the Brumbies were better as a result of his time at the club.

"I think we can be pretty proud of what we've done here. Finals didn't come easy, in my first four years here we never made one so to say we made four in a row and a final, obviously we didn't get any silverware, but there's still a lot there to be proud of," he said.

"It's been a big ride, been a huge part of my life. I moved away from my family to come down here so it's very much been my family here.

"I've loved every minute of it, sad I couldn't get anyone some silverware, but hopefully leave the place in a better state than it was when I came here.

"You always dream of leaving on a real nice note, but in saying that I leave with a heavy heart as well and that's a big thing," Toomua said.

"I really love this place, love the people, and I've come to love the city as well. It's been a big part of my life. Sometimes it doesn't end the way you dream it up, but that's fine."

There is a possibility Toomua could return to the club where he played 88 Super Rugby games, but for now he views the loss to the Highlanders as his last game for the Brumbies.

He has no regrets about his decision to leave, which sees both him and wife Ellyse Perry to ply their respective sporting trades in England.

But first he has farewells to say to his Brumbies teammates. Then there's the possibility of a Wallabies campaign as well.

He's played 32 Tests for Australia and could add to that in the upcoming Rugby Championship.

"I haven't heard anything about the [Wallabies] squad being named so I'll keep my bags packed," Toomua said.

"It's something that I'll have to quickly switch over to, but before that's done I've got to do this place justice and say goodbye properly. We'll see what happens.

"[England is] too far away. I never wanted to put one foot in both camps.

"I wanted to commit here and not commit there, compartmentalise a little bit and when the time comes I'm sure I'll have a think about it when I fly over."