Dreams into Reality


Kosaku went from being a beginner triathlete to an IRONMAN finisher within a year.

From barely able to swim 25m to completing his first open water swim in the MetaSprint Series Aquathlon, then putting the three disciplines together in the MetaSprint Series Triathlon and finally stepping up to Olympic and half IRONMAN distance at the Bintan Triathlon and IRONMAN 70.3 Bintan.

How did he manage? What does it take?

Athlete profile:


1. Congratulations on finishing Ironman Malaysia! When and where did your triathlon journey start?

My triathlon journey started in May 2017 when I met my ex-boss in Tokyo. He had just completed his first sprint distance triathlon in Hawaii and asked me to join him in 2018. At that time, I was more interested in mountaineering and training for climbing Kilimanjaro (5895m – highest mountain in Africa) that September. We promised to meet at Kilimanjaro and then again in Hawaii in May 2018, without any intention to really do so. However, back in Singapore I started to like the idea and decided to give it a shot.

While climbing Kilimanjaro I met someone who had done a few triathlons. He urged me to register for the Olympic distance instead of the Sprint. The thought of swimming 1500m instead of 750m was daunting. ‘I will probably curse you’ I said. ‘No, you will thank me.’ he responded. And so I registered for the OD in Hawaii, and texted my ex-boss. However, he couldn’t make it and not much later I had to cancel my travel plans as well. Fortunately, I found a beautiful alternative; the Bintan Triathlon!

2.  What motivated you to try your hand at triathlon?

To be honest, I was not interested in triathlon until my ex-boss asked me to join him. I agreed to it, because I like him a lot. If it wasn’t for him, I would not have started triathlon. I like a challenge though, and that’s why I now LOVE this sport.

3.  Did you have any swimming, cycling or running experience prior to starting triathlon?

I only had a little bit of running experience. I ran the Singapore Marathon in 2012 and 2014. My knee always started aching after 15km-20km and it took me almost 7 hours to finish both marathons. Taking advice and training tips from a colleague, I started training properly for the 2017 edition and completed it in 5h23.

I only started training for the swim in December 2017. I would swim 25m, be completely out of breath, rest 2min and do that for 30-40min. I posted on Facebook ‘Just because I’m not good at swimming doesn’t mean that I shouldn’t try’.

4.  From Sprint Distance to Ironman within a year is a big leap. How did you manage to build your endurance level? What were the biggest challenges?

My colleagues helped me plan my training. I started swimming 6 days a week and run more frequently. My running coach told me to not rest more than 2 days between runs and I read in an article that on average athletes train between 12-17 hours per week for an Ironman.

I trained almost every day, even if it was for 20-30min. On weekdays I woke up early to swim for 30-60min before heading to the office and during lunch time I would spin or run for another 30min. On weekends I did my long runs and brick training. I gradually increased the mileage and at some point ended up running 42km just for training, which was quite fun.

Time management was one of the biggest challenges as I progressed from the MetaSprint Series to the Bintan Triathlon Olympic distance to Ironman 70.3 Bintan, and eventually the full Ironman in Langkawi. Especially when I changed team at work and needed to work longer hours just 2.5 months before my first Ironman 70.3 in Bintan. Giving up wasn’t an option, so I decided to run 9km home twice a week. It happened to be only 5-10min slower than taking the MRT!

5. How did the MetaSprint Series, Bintan Triathlon and Ironman 70.3 Bintan prepare you for your Ironman? What were the big learnings?

Instead of having a big goal 1 year later, racing almost every month and setting goals for each race helped me to stay motivated and step up each time.

For me, it was all about my swim. The MetaSprint Series was a perfect choice to start my triathlon journey. It started in February with an Aquathlon (Swim-Run). I still remember panicking after 5-10min at my first open water swim practice. The Aquathlon went very well, though. I completed the 750m swim in the protected bay of Sentosa without much problems.

Next up was the MetaSprint Duathlon (Bike-Run) in March, which was pretty smooth sailing, and then in April I finally stood on the start line of my first triathlon. The sea at East Coast Park looked calm, but when I got into the water, it was actually quite choppy and I was pushed by the current. I was out of breath after 300m, had to start swimming breaststroke and even grabbed the course rope a few times to rest. At that moment I thought doing an Ironman was impossible.

Despite the difficult race at the Metasprint Series triathlon, I still pushed myself to race the Bintan Triathlon Olympic Distance in May. Being a pretty optimistic person, I thought that if the water was going to be calm in Bintan I should be okay. I was right! I started ridiculously slow and realized that I could then continue to swim for a long time. 1500m ticked! The step up to Ironman 70.3 Bintan was easier. I thoroughly enjoyed the whole experience. (I was like a baseball kid playing a game in Yankee Stadium!) Knowing that I could go the distance in all three disciplines set me up nicely for my first Ironman.

The biggest learnings from this journey is that with a lot of practice, anything is possible! …and don’t try anything for the first time on race day.

6. You achieved your goal of completing an Ironman. What is next?

I will enjoy a little bit of off-season as a triathlete. First, I will be climbing Aconcagua (with 6962m the highest mountain in South America) in December – I want to climb the ‘Seven Summits’. Then in March, I will be running Tokyo Marathon – I want run all the World Marathon Majors (even though I’m nowhere near qualifying for Boston ..yet!).

My ultimate goal as a triathlete is, of course, to race in the World Championships in Kona one day. Whether I have to race (at least) 11 more full Ironmans and have enough luck to be selected, or continue long enough to win a race when I’m in the age group of 70-74 and qualify directly.

7. Any final advise to anyone who wants to follow in your footsteps?

Register for a race first. Commit to a goal. I signed up for Ironman 70.3 Bintan in December when I was still struggling to swim continuously more than 200m. Just sign up and think about how you are going to make it happen later.

Don’t set yourself limits. If many other people have already done it, most likely you can do it too.

It helps if you are a social media addict like me. Even if you are tired in the morning you go training, because you want to tell the world that you woke up at 4am to exercise. You run more than you want to, because you like to show off. Because you are an Ironman in training! Oh, and don’t forget to follow my Instagram account, ‘bokenka.kosaku’.

I made some very good friends through triathlon. The triathlon community is almost like a family. Join us! you will love it!


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