10. Tim Don, 39, Great Britain
As a three-time Olympian, 2006 ITU world champion, former 220 Triathlon columnist and multiple winner at middle and long-course racing, Don’s appetite for competition is unrelenting. Now 39, it seems he is moving faster than ever - achieving automatic qualification for this year’s race by setting a new Ironman-branded record of 7hr 40min in winning the Ironman South American Championship in Brazil.
The Londoner who's now based in Boulder, Colorado, biked a remarkable 4:06hr – 20mins faster than his closest rival – on the Florianopolis course, but the bike leg in Hawaii still presents his most significant challenge. The largely out-and-back bike route along the Queen K highway is suited to strong bikers that can generate enormous power or punch through strong winds. As his two appearances to date - a 15th in 2015 and a DNF last year - would suggest, it doesn't favour Don. However, he's in shape for his best performance yet, as an impressive third place in a stellar field in September's Ironman 70.3 World Championship showed.
9. David McNamee, 29, Great Britain
McNamee has finished the best-placed Brit in Kona in each of the past two seasons and would be the safest tip to do so again. The Scot has continued to improve every season since stepping away from draft-legal ITU racing as a lottery-funded triathlete in 2014. Comfortably good enough to be in the front pack in the swim, it'll be damage limitation on the bike before his strength kicks in as he builds through a patient marathon to pick off places on the run.
In 2015 it resulted in the fastest marathon and 11th place and last year he was two spots further back in 13th. A third-place in Ironman South Africa this season has been complemented by a trio of middle-distance victories at Ironman 70.3 Dublin, 70.3 Mallorca and Challenge Salou in Spain, and if everything goes to plan, then a top 10 finish isn't beyond his grasp.
8. Tyler Butterfield, 34, Bermuda
For a small island in the North Atlantic, Bermuda punches well above its weight in triathlon, thanks largely to the exploits of reigning ITU world champion Flora Duffy. Now it’s Butterfield’s turn and, while the two-time Olympian shouldn’t struggle too much with acclimatising to the oppressive heat, he's proved hit or miss on the Big Island, with three finishes in five starts. A seventh-place in 2013 was followed by a DNF in 2014, an improvement to fifth in 2015 and another aborted attempt last year.
After a win at 70.3 Raleigh, Butterfield picked up the bulk of his qualifying points with a solid third-place in the Ironman North American Championship in Texas in April – where he just held off fast-finishing Brit Will Clarke on the run. Butterfield then failed to finish Ironman Boulder due to mechanical issues, but perhaps a better indicator of his form is the recent Ironman 70.3 World Championship where he finished a strong seventh in a stacked field to suggest he's peaking at just the right time.
7. Frederik Van Lierde, 38, Belgium
If Van Lierde is a steady if unspectacular racer, then his build-up to this year’s Ironman World Championship has been anything but. Having won Ironman Cozumel in November, he was set for a tilt at Ironman South Africa in Spring before being mugged and knocked unconscious on a training run in Port Elizabeth. He still made it to the start and recovered enough to finish seventh. In Ironman France he cracked his head on a cooling shower on the run course and was left covered in blood and needing medical attention before fighting back to win.
The bash on the bonce aside, the victory in France could provide to be a good omen for Van Lierde as it was the same path he took before winning the Kona title in 2013. If he's to improve on last year’s 10th place, he’ll also need to avoid another hazard of racing – the draft marshals. The Belgian picked up a stop-go penalty last year that saw him lose the leaders on the bike, and he simply doesn't possess the speed to make it back on the run.
6. Tim O’Donnell, 37, USA
Whether O’Donnell turns up to Kona with fresh motivation or a sleep-deprived shell will depend on what effect becoming a new dad has - the American welcomed daughter Isabella Grace to the world on 22 August. It does mean – that for this year at least – he'll be the primary focus of the family’s attention when it comes to racing in Hawaii as his other half, the three-time Kona champion Mirinda Carfrae, settles into motherhood.
Carfrae is part of an enviable support cast that also includes six-time Hawaii winner, Mark Allen, as coach. O’Donnell has kept racing closer to home in Boulder this year, winning his home town Ironman comfortably in 8:13hr, alongside a number of podium finishes in 70.3 events. If those results don't look world-beating then it's his history of four top 10 finishes in Kona - including third in 2015 - that mark him out as a contender.