2018 Flanagan claimed his first major professional victory in the 2018
Falmouth Road Race, running the 7 mile course in a time of 32:21. On September 4, 2018, he joined the
Reebok Boston Track Club in
Charlottesville, Virginia to be coached by Chris John Fox.
2019 Flanagan made his professional debut on January 26, 2019, at the Dr. Sander Columbia Challenge at the
Armory in
New York City. Contesting the
3000 m, he took first, running a personal best of 7:48.80. Two weeks later, he returned to the Armory once again to compete in the 3000 m at the
2019 Millrose Games. He placed 10th in a time of 7:54.40. Flanagan opened his outdoor season competing at the
BAA 5K, placing fourth in 13:49. Competing over 10,000 m, he set a personal best of 28:19.51 in Palo Alto on May 2, and won the Canadian title in the event the next month in Burnaby.
2020 Ben opened his 2020 campaign on January 25 at the
New Balance Indoor Grand Prix running 7:56.02 over 3000 m. The next month competing at Boston University he ran personal bests over 3000 m (7:47.37 on Feb 15) and 5000 m (13:31.07 on February 28). Despite competing sparsely due to the COVID-19 pandemic, Flanagan managed a 10,000 m personal best of 28:06.88 in August. In December, he made his half marathon debut, taking the win in
Hardeeville, South Carolina in 1:03:19.
2021 In 2021, Flanagan failed to qualify for the postponed
Tokyo Olympics. He achieved the necessary world ranking, but was beaten out for a spot on the Canadian team by
Moh Ahmed,
Justyn Knight, and
Luc Bruchet. Nevertheless, Flanagan ran a 10,000 m personal best of 27:49.07 on May 14 and a 5000 m personal best of 13:20.67 on May 27. On the roads, he won his second
Falmouth Road Race in August and won his first
Manchester Road Race in November.
2022 On January 12, Flanagan announced on Instagram that he was leaving the Reebok Boston Track Club. The next week, he announced that he had signed a contract with
On and was moving back to Ann Arbor to train with the Very Nice Track Club under coach
Ron Warhurst. Under Warhurst, Flanagan continued his success on the roads, setting a Canadian 10 km road record at the
B.A.A. 10K in 28:11 and winning his third Falmouth Road Race in 32:25. On October 23, Flanagan competed in the
Valencia Half Marathon. While he only finished 18th overall, he beat fellow Canadian
Cam Levins by 4 seconds, and broke
Rory Linkletter's Canadian half marathon record holder with a time of 1:01:00.
2023 Flanagan opened his season on January 27 with a personal best of 13:11.97 over 5000m at the BU John Thomas Terrier Classic. The following week, he set a personal best of 7:43.49 in the 3000m at the
New Balance Indoor Grand Prix. At the
B.A.A 5K in April, Flanagan broke
Charles Philibert-Thiboutot's Canadian record in the 5 km road race, running 13:26 and finishing second behind training partner
Morgan Beadlescomb. At the 2023
Canadian Track and Field Championships, Flanagan won the 5000 m in a time of 13:39.36. Later that summer, he qualified to represent Canada at his first
World Athletics Championships in the 5000m, where he finished 11th in his heat with a time of
13:38.69. In October, he represented Canada in the inaugural 5 km road race at the
2023 World Athletics Road Running Championships in
Riga, Latvia, finishing 12th in a time of 13:34.
2024 On January 26, Flanagan entered the 5000 m at the John Thomas Terrier Classic in Boston with the goal of achieving the Olympic standard of 13:05.00. Coming through the 3000 m mark in 7:55.01, he reached 4800 m in 12:36.78, needing a last lap of 28.22 or faster to hit the standard. Trailing noted fast-finisher
Geordie Beamish, he closed his lap in 27.85, the second fastest finishing lap of anyone in the field (besides Beamish). With that, he ran a time of 13:04.62, hitting the Olympic standard, making him eligible to be selected to represent Canada at the 2024 Olympics. On February 4, Flanagan finished 4th in the 3000 m at the
New Balance Indoor Grand Prix, running a personal best of 7:40.19. After his brief indoor season, he embarked on a six-week altitude camp in Boulder, Colorado, training alongside members of the
On Athletics Club in preparation for the
Sound Running TEN on March 16, a 10,000 m race in
San Juan Capistrano, California. At the TEN, Flanagan ran a time of 27:20.93, eclipsing his previous personal best time by almost 30 seconds. The mark placed him third on the all-time Canadian list, only behind
Moh Ahmed and
Cam Levins. == Competition record ==