River Kwai Half Marathon – Race Review

River Kwai International Half Marathon is Thailand’s oldest road running race, 2014 marked the 33rd edition of the event. It’s a popular race and this year it was sold out almost a month in advance even though they opened up for over 2,000 runners instead of maximum 1,500 as initially was announced. Next year’s race has a maximum capacity of 2,500 and I’m sure it’ll be fully booked again.

Why is this half marathon in Sai Yok (Kanchanaburi) so popular?

+ The beautiful out and back course. You have the River Kwai on one side, mountains on the other side and green nature on both sides.
+ The first half of the race is challenging as it’s mostly uphill, consequently the second half is way faster. You’re likely to get a big negative split and you can gain speed, especially in the last 5k where the incline is perfectly steep for letting the legs just roll down to the finish.
+ It’s a nice “destination race”. Kanchanaburi is only a 2-3 hour’s drive from Bangkok and offers various tourist attractions for those who want to do more than just run.
+ It’s a fairly well-organized race, no real complaints about the event and its organization.

Any downsides about the race?

– Can be difficult to find accommodation nearby the start/finish unless you book well in advance. It won’t be easier next year with 2,500 runners even though the hosting race resort is expanding.
– It’s not a very competitive race (no prize money) and don’t expect to break your PR on the hilly course.
– With an increase in number of participants, the organizer may consider to separate the starts of the half and mini marathon.

Winning the River Kwai Half Marathon

My two goals for the race were to win it for the 5th consecutive time and improve last year’s finish time of 1.14.20. The weather was great and I just wanted to keep a decent pace to the u-turn, then switch it up a notch and finish with a really strong final 5k.

I was averaging 3.42/k for the first 5k and 3.09/k the last 5k. The total average pace was 3.28/k (Garmin 21.25k in 1.13.39). Mission completed, both goals fulfilled; I won and I did it in 1.13.39. All results.