As Alex Yee gears up for his first-ever marathon at the 2025 London Marathon, all eyes in the endurance sports community are on the Olympic triathlon champion. Yee, 27, is stepping into new territory—but he’s no stranger to London’s famous marathon day. Growing up in Lewisham, he regularly raced the mini-marathon as a child. “London gave me so much growing up,” he said. For Yee, taking on the full marathon was simply “a no-brainer.“
Switching Gears: From Triathlon to Marathon
Making the jump from triathlon to marathon isn’t straightforward, even for an athlete of Yee’s caliber. Known for blazing fast times at shorter distances, he’s working closely with longtime coach Adam Elliott to tailor his training. Instead of the typical marathoner’s 100+ mile weeks, Yee is topping out around 80 miles weekly—still high for triathlon standards but modest compared to marathon legends like Eliud Kipchoge, who often hits 130 miles.
- Yee’s weekly mileage: ~80 miles
- Typical elite marathoner’s mileage (e.g., Kipchoge): ~130 miles
“We’re aiming for a good performance without risking injury by overdoing mileage,” Elliott explained. “We want to find the sweet spot.”
Keeping Triathlon in the Mix
Interestingly, Yee isn’t leaving behind swimming or cycling, which remain key parts of his training. He and Elliott believe these disciplines help maintain aerobic fitness without the higher injury risk associated with heavy running mileage.
- Weekly cycling: ~10 hours
- Weekly swimming: 4-5 sessions
Elliott notes that while they might dial back the intensity on the bike slightly as marathon day approaches, swimming remains crucial to Yee’s long-term triathlon goals. “Alex has worked hard to reach this swim level, and we don’t want to lose that,” Elliott said.
A Peek into Yee’s Training Stats
Yee’s marathon prep isn’t just impressive—it’s meticulously tracked. Recently, during a tough 30km progression run, Yee started comfortably, hitting the first 5K in 17:21 (about 5:35 per mile pace) with his heart rate at an easy 143 bpm. From there, he cranked it up, maintaining an impressive 4:56 per mile pace (3:04 min/km) for the next 20km, his heart rate climbing steadily to 172 bpm.
- First 5K: 17:21 (5:35 per mile), 143 bpm heart rate
- Middle 20km: 4:56 per mile (3:04 min/km), 172 bpm heart rate
- Final 5K: 14:50 (4:47 per mile), 177 bpm heart rate
- Overall average pace: ~5-minute mile
Remarkably, even after 25km, Yee found another gear, a clear indication that a marathon finish between 2:07 and 2:10 could be within reach.
Where Would Yee Stand Historically?
If Yee hits his goal, he’d instantly land among the top five British marathoners of all time—an incredible feat for someone whose main sport isn’t even running. Historically, triathletes have rarely excelled at the marathon, making Yee’s ambitious goal particularly intriguing.
- Yee’s target marathon time: 2:07–2:10
- Top British marathon time (Emile Cairess, 2024): 2:06:46
For context, British marathon star Emile Cairess ran 2:06:46 at last year’s London Marathon, joining the elite sub-2:07 club alongside Olympic legend Mo Farah. If Yee can approach those times, it’ll redefine what’s considered possible for a triathlete.
The Bigger Picture
For Yee, however, this marathon is more about exploration and challenge than setting permanent records. With the 2028 Olympics in Los Angeles still on his radar, Yee views the London Marathon as an opportunity to push himself in new ways.
“I don’t feel like a complete triathlete yet,” Yee said. The marathon is part of his broader plan to see how far he can push his endurance—and then translate those gains back to triathlon.
As London eagerly awaits race day, Yee’s marathon debut promises to be exciting, not just as a test of speed and stamina but as a rare experiment in cross-sport endurance excellence.
