Hamer has been a middle distance runner for the past decade but last year made the switch to marathon running and qualified for April's Gold Coast Games in his first attempt.

The 29-year-old was set to run the 10,000 metres at the Glasgow Commonwealth Games four years ago but was forced to pull out with an Achilles injury.

Hamer moved to Canberra four years ago to work with Dick Telford and the world-renowned coach suggested he give the marathon a crack.

That same Achilles injury threatened to derail his marathon career before it even got going when he required surgery in 2015.

Hamer had a part of his Achilles cut out - but that didn't work. So the next year he was back under the knife and surgeons were forced to cut out a piece of bone from his foot.

"It's funny, because every time you get surgery the surgeon will tell you it's about three to six weeks," Hamer said.

"For me it ended up being about eight or nine months before I could actually do anything. It was just a lot of rehab and physio and that sort of stuff.

"I'm probably a bit different to most of the athletes because I've got a full-time job [as an accountant]. I just focused on that and didn't worry too much about it, I gave it a bit of time and thought about other things.

"I'd always thought I would get back, it just took a lot longer than I thought it would."

Hamer has his spot locked up but a host of fellow Canberra athletes could be forced to wait until Thursday to learn their Commonwealth Games fate.

Sprinter Melissa Breen is among those relying on a discretionary selection as she eyes one of the 31 places left in the squad, with Athletics Australia required to submit their nominations to Commonwealth Games Australia by Thursday.

Hamer has been given a few weeks of unpaid leave from work to head up to the Gold Coast and start preparing for a marathon in humid conditions.

The money won't be flowing in but Hamer says the chance to get away early could work wonders in the lead up to his second marathon - because it will soon start to get cold in Canberra.

"The qualifier is 2:19 and without sounding too arrogant I was pretty confident of getting that, the time isn't so hard to get, it's a matter of being in the top three Australians to get a position on the team," Hamer said.

"I've qualified because I have a great coach and he knew I was going to be better suited to longer distances, it was just a matter of more consistent training without getting injured.

"I haven't really thought too much about position or time. Dick is one of the best in the world for marathon so I'll just listen to him and I'm sure the result will take care of itself.

"It's the last race on the schedule which is cool and it's really exciting to be racing in Australia and that all my family and friends can come, it's pretty special."

"It was obviously pretty disappointing missing out last time, that would have been my first major championships, but this time I'm in a much better position and better prepared."

Not only does he have ACT Brumbies fitness guru Ben Serpell to lean on in preparation, he has "the best distance coach Australia has ever had" behind him in Telford.

Canberra athletes confirmed for 2018 Commonwealth Games:

Lauren Wells - 400m hurdles

Cameron Crombie - F38 shot put

Chris Hamer - marathon

Evan O'Hanlon - T38 100m

Skye Nicolson - boxing (AIS based)

Christine Nunn - squash

Chloe Hosking - cycling (road race)

Zoe Buckman - 1500m

Kelsey-Lee Roberts - javelin

Click here for a full list of Australian athletes competing at the Commonwealth Games.