Alex Yee’s watch data predicting SENSATIONAL marathon time ahead of Valencia

If he can match the predicted time from his watch then Olympic triathlon champ would become second-fastest Brit of all time over 26.2 miles.
News Director
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Olympic triathlon champion Alex Yee is into the well-known ‘maranoia’ stage after a smooth build up to his crack at the Valencia Marathon on December 7th.

He’s triathlon’s fastest male runner and this year took the opportunity in the season after his Olympic triumph in Paris to achieve a lifetime’s ambition of running in the London Marathon.

And the Brit finished a superb 14th there in a time of 2:11:08 despite unusually hot temperatures for the end of April which meant that the majority of runners – elites and amateurs – clocked a slower second half.

Feeling there’s more to come from him over 26.2 miles, he announced a few months ago that he would be racing Valencia, which is traditionally one of the world’s quicker marathons, before returning to swim / bike / run.

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Elite training partners

He’s been documenting his training and preparation on his YouTube channel and things appear to have gone very much to plan.

Plenty of his training has been with top British marathon runner Phil Sesemann, who will also race Valencia, and more recently Emile Cairess, who was fourth in the marathon at the Paris Olympics.

Yee also took in the Valencia Half Marathon in late October where he was slightly disappointed with a time of 1:01:29 as tests beforehand had suggested something under 61 minutes was in the offing, “maybe close to 60:30”.

However windy conditions played their part and underline that predictions are just that and can be skewed by a whole range of factors, including the race dynamics.

Alex Yee London Marathon 2025
Olympic triathlon champion Alex Yee made his London Marathon debut in 2025 (Photo – TCS London Marathon).

‘Let’s see what can happen’

But they are also calculated using months worth of data and posting on Instagram Yee said: “Maranoia is on my mind but i’m excited to have one last go at the marathon distance. With the experience of London, my biggest run block (5 weeks over 100miles!) and the new COROS PACE 4 on the wrist, let’s see what can happen València.. VAMOS”

One of the photos alongside is from that COROS watch and shows the latest predicted times for the most popular distances – and it makes for fascinating reading.

His 5K ‘race predictor’ is 13:37 and his PB on the road is 13:26 from the Podium 5K in Barrowford in 2020 while he also ran a 13:13 5,000m on the track in Belgium in August this year.

His 10K prediction is 28:01, again very close to his quickest road time (28:05) which came in Valencia ahead of London this year.

The half marathon comes in at 1:01:01 so a bit quicker than that 1:01:29 but as he said himself after the Valencia half, conditions weren’t ideal and he was hoping for sub-61.

All of which brings us to the potential marathon time. There have been hints that 2:07 was the ballpark target time but the COROS suggests even quicker than that – 2:05:46.

Alex Yee Valencia marathon training looks at COROS watch
Alex Yee heads next to the Valencia marathon [Photo credit: COROS]
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Where would that time rank?

As a caveat, the further up in distance you go there’s more scope for variance, especially the marathon where those last few miles can make or break a race.

But it’s still hugely encouraging – as is the fact that Yee is willing to share it.

RELATED CONTENT: What is a good marathon time?

To put it into context, the fastest ever time by a British man in a marathon is Sir Mo Farah’s 2:05:11 at the Chicago Marathon in 2018. The next best is Cairess’ 2:06:46 at the London Marathon last year.

And training partner Sesemann underlined how well his Valencia prep is going when he set a new PB and moved to fifth on the all-time list with a 2:07:17 in Amsterdam in October.

So if Yee gets anywhere near those times then it is rarified company indeed, especially for someone who is an Olympic champion in a different sport.

Jonathan Turner
Written by
Jonathan Turner
Jonathan Turner is News Director for both TRI247 and RUN247, and is accustomed to big-name interviews, breaking news stories and providing unrivalled coverage for endurance sports.  
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