Shonan International Marathon (2025)
Race report 20: Third Shonan International Marathon
20th Shonan International Marathon (第２０回湘南国際マラソン) : 7 Dec 2025
This year (2025) was my third time to run the Shonan International Marathon. The details of the course are exactly the same as first time (consistent marathon) so if you would like details about the marathon itself I recommend checking out my first report, which can be found here.
Lead up to the race
At the end of October this year I got a little sick. I went to Singapore and got worse while I was there (being diagnosed with pneumonia when I got back to Japan), but I largely recovered after a few weeks. I spent the two weeks before the marathon in Europe (on business), and while I did run there I felt a little under trained and jet lagged when I got back to Japan.
I decided to try to aim for sub-3 anyway, but with the back up of a marathon PB, a Shonan Marathon PB, and of course, finishing the race with a smile.
20th Shonan International Marathon (7 December 2025)
Race morning
This year I decided that I didn’t want to wait for the bus at Oiso so I walked the almost 4 km to the Prince Hotel from Oiso station. This acted like a good warm up. The weather was pretty pleasant even at this time of the day but I knew it was forecast to get quite hot as the marathon went on.
It took quite a while for me to get to an area that I could drop off my bag. The crowds coming in from that side were quite intense. I eventually dropped off my bag then went to the area close to the A block to get ready for the race. This year there was a system where toilets were available based on blocks. I managed to take a final trip to the restroom and as soon as I was done the runners had already gone to the starting area.
I met a few friends of mine in the area and one of my friends spotted the sub-3 hour pacer group I was intending on running with this time. I followed the pacers then got ready to start the race.
The race started at 9 am and I stuck as close as I could to the 3 hour group for as long as I could. To run a sub-3 hour marathon you need to maintain a pace of 4:15/km. The pacers at the start were running at 4:10, and running with them managed to get me an all time personal best for my 10K. Unfortunately I was not able to keep that pace going and eventually ended up dropping off. I was going to run my own race at that point because a sub-3 hour marathon was clearly not sustainable in my condition on the day.
Support for this marathon was absolutely fantastic. Over the year I’ve been running in the area I’ve made a lot of friends, and the ones who weren’t running the marathon came out to support. People were calling after me by name on many points of the course. I got a lot of high-fives and received a lot of cool pictures after the race was done.
I managed to keep going quite reasonably until the turnaround point at around 19 km. I then started falling apart and feeling quite unwell. As I was crossing the bridge to leave Fujisawa one of my friends called after me to tell me to drink lots of water. I took this advice to heart to see if it would improve my condition and started taking water breaks every few water stations. (Reminder that the Shonan International Marathon has water stations every 200 meters but you need to use your own cup. No paper cups at aid stations).
I kept taking drinks, walking with the drinks for a bit, and then setting off on a run again. This was a good strategy to bring my heart rate down and refocus myself, but I was getting worried that my pace was dropping. Outwardly, I didn’t look too bad but I was fighting for my life.
I kept my strategy going of drinking water/sports drink and making my way towards the finish line, and started to feel better as I started closing the distance to the finish. By the time I reached 36 km I was reducing my drink breaks and just kept heading towards the finish.
At around 37 km I could see the finish line, but also the sub-3:30 pacers caught up to me. Everyone was moving pretty rhythmically so there was a lot of noise coming from that pacer group. They briefly overtook me, but I upped my pace to make sure I got ahead of them, then used them as a marker to run my own race. As long as I kept ahead of them I’d get a sub-3:30 marathon and the quieter those foot falls got the more time I had to play with. I kept that strategy up until the end.
I increased my pace even more as I closed in on the finish line and ended up passing some of my friends who had overtaken me earlier. I gave them some encouragement as I went by but was totally locked in on Finishing the race.
The very end of the race has a small uphill section followed by a funnel leading to the finish. I charged through that area and comfortably finished in under 3 hours 30 minutes.
After the race
Immediately after the race I picked up my medal then met a few friends, then went to get a picture taken with the podium. Coincidentally the award ceremony was just about to start and a good friend of mine (Sakamoto San) had finished in 3rd place.
This was a rough marathon for me. My condition wasn’t great and I didn’t feel 100% on the day, but I still managed to get a decent result and had a lot of fun on the day. Although it was probably my hardest Shonan International Marathon, it was the one with the best support.
Results
It’s probably reasonable to compare my results with previous Shonan International Marathons.
Shonan International Marathon (2022): 3:33:38.
Shonan International Marathon (2023): 3:28:20
Shonan International Marathon (2025): 3:26:32
I managed to cut off a few minutes from my Shonan personal best time, but it was still quite a way off my overall personal best time, which I got at the Shizuoka Marathon earlier in the year (3:15:43).
(The official results have not been announced yet so I will update this later). I came in XXXth place (XXX/14480) in my category and XXXth place overall (XXX/17,343).
Below is the race medal:
Below is the online certificate I received:
And finally here is the pace data from my watch. You can clearly see the drop off and the number of short breaks I needed to take.
Lessons learned
The Shonan International Marathon is quite a difficult marathon to do well at. For me anyway. The lack of water at aid stations means that fluid management is put on the runners. Though there are a lot of water stations the time loss associated with them is significant.
It might not be fair to blame the water stations alone though. My physical condition wasn’t great on the day so I need to try to make sure I have better preparation before the next marathon.
Final thoughts
Though this was a difficult marathon for me and I fell short of my primary goals, I had a good race, came in with a respectable time and had fun on the day. I also had a lot of friends complete their first ever marathon on that day and my good friend came in 3rd place. Great result all around.
When I think about it, this was my 10th official race of marathon or greater distance. Lots more to do. Let’s get after it.
Thank you very much for reading. If you enjoy my work please share it with someone you think would also enjoy it.
If you aren’t subscribed, please sign up to keep up to date.
If social media is more your thing I’m active on Facebook, Twitter, and Instagram.
And if you are looking for ways you can support my work please check out the page below:
Osu!
Anthony