These are the top 20 debut marathons in history. Strictly speaking, some athletes listed below may have started previous marathons and failed to finish. But “fastest time achieved in the first marathon they completed” wasn’t really a catchy title, so I’m sticking with the word debut. Either way, I’ve marked such athletes with an asterisk.

I’ve also included Moses Mosop’s time in the list, but only really for reference as it was set on Boston’s point-to-point course.

What’s striking is how recent most of these are, especially on the men’s side. All but one of the men’s top-20 debuts have been achieved in the past four years and the top six times (exluding Mosop) have all been set between 2012-2013.

When Gebrselassie ran 2:06:35 in 2002, that was the fastest debut in history at that time. Now, it’s not even fast enough to make it into the top 20.

There is more of a spread in the women’s list, in terms of both times and the years in which they were achieved. Also, many of the recent marathon stars had unremarkable debuts before hitting the big time a few years later. Olympic champion Tiki Gelana ran 2:33:49 in her first marathon in 2009, then won the Olympic title just three years later. Two-time world champion Edna Kiplagat clocked just 2:50:20 in her first race over the classic distance, while former London Marathon winner Mary Keitany only just sneaked inside 2:30 on her debut.

As ever, any additions and corrections are welcome. I’ll try to keep this page updated as often as I can, as I always seem to struggle to find a definitive source of the fastest debut marathons.

Men

Debuts of other notable athletes

Women

Debuts of other notable athletes

* This was their first completed marathon. They had previously attempted another marathon but failed to finish.