Kenyans Violah Jepchumba and Cyprian Kotut will aim to continue their strong 2016 momentum at the Cardiff Half Marathon, an IAAF Bronze Label Road Race, on Sunday (2).
The 25-year-old Jepchumba has been on a tear on the road racing circuit this year, running undefeated in four events from early April through September. On 2 April, she clocked 1:05:51 at the Prague Half Marathon to move up to the number two spot on the all-time lists with the fourth fastest performance in history.
She followed up with dominating performances at half marathons in Istanbul and Gothenburg and after a three-and-a-half month break from competition, returned to action at the Prague 10km on 10 September where she clocked an African record 30:24, just three seconds shy of Paula Radcliffe's world record set in 2003.
How fast she'll run this weekend is anyone's guess, but she'll clearly arrive in the best shape of her life.
On paper her closest adversary is Flomena Daniel, the 2014 Commonwealth marathon champion. Daniel has a 1:07:39 best with her 2:22:44 marathon lifetime best dating back to the 2014 Paris Marathon.
Others to watch include Lenah Jerotich, the defending champion, who produced her 1:11:31 best on the Cardiff course.
Uganda's 19-year-old Rachel Chebet-Zena, a 5000m finalist at this year's African Championships, will be making her debut over the distance.
Kotut meanwhile, has also produced a pair of solid victories in 2016. The 24-year-old improved his personal best to 2:07:11 to win the Paris Marathon in April, and warmed up for that one month earlier with a 1:01:00 victory in the Paris Half Marathon. He ran his 59:12 lifetime best in New Delhi in 2014.
His chief opposition is expected from Uganda's Ben Siwa, who returns to defend his Cardiff title. He ran his 1:02:06 best in the Welsh capital last year.
Paul Pollack of Ireland is the third fastest man in the field at 1:02:10 and returns to action after his 32nd place finish in the Rio 2016 Olympic marathon where he clocked 2:16:24.
Others to watch include Shadrack Korir of Kenya who brings a 1:02:40 personal best to the line and Charles Muneria, also of Kenya, who'll be making his debut over the distance. The 20-year-old was second at the notoriously difficult Kenyan Olympic Trials to qualify for the Rio Games where he finished a distant 12th in his heat.
Local attention will fall on Dewi Griffiths, a three-time Welsh marathon champion, and Michelle Rosse-Cope, with a best of 1:12:01.
Bob Ramsak for the IAAF