Moira Koster (nee de Villiers) was born on 16 March 1990 in Johannesburg, South Africa. She is in the -78kg weight category in Judo. Koster is a highly skilled New Zealand judoka with a rich competitive history, having participated in five World Championships from 2010 to 2023 and in two Olympic Games from 2012 to 2024.
She earned a silver medal in the -70kg category at the 2014 Commonwealth Games in Glasgow and a bronze in the -78kg category at the 2022 Commonwealth Games in Birmingham.
This makes Koster one of New Zealand’s most experienced female judokas, having won multiple medals, including gold, silver, and bronze at Continental Opens, a bronze at a World Cup, and two medals at the Commonwealth Games
Throughout her career, she has been a prominent figure in the Oceania Championships, securing multiple medals, including ten titles dating back to her junior years. Koster has also collected 14 World Cup medals, highlighted by her victories at the 2022 African Open in Tunis and Algiers in the -78kg category.
Born Moira de Villiers, she is married to fellow Judoka and coach, Jason Koster. A notable moment in their career was when they both medalled at the 2014 Commonwealth Games.
Koster’s journey to the Paris Olympics has been challenging. She faced a significant setback in April 2024 when she suffered a serious injury during the Pan American Games. Despite this, her determination and rigorous rehabilitation enabled her to regain her fitness and secure her place on the Olympic team.
What initially drew you to the sport of Judo?
The nursery school I attended had a Sensei who came and taught classes. I remember seeing only boys and thought to myself, “If they can do it, so can I.” I was a bit of a tomboy back then and believed I could take them on.
What should young athletes keep in mind when setting goals and measuring their progress?
Remember your why. Why do you do what you do? A great measure is to determine what you want to achieve in your judo career and continually strive towards that. Don’t let anyone try to stop you!
How do you handle setbacks and injuries, and what advice would you give to athletes facing similar challenges?
Injuries can sometimes be a blessing, as hard as they are to deal with physically and mentally. They teach you to go back to basics and focus on what you can control.
A mental skills coach once told me something great: do simple better! When I have an injury, I just do the simple things as best I can and keep moving forward.
How did you transition from competing in the 70 kg to the 78 kg weight class?
After having my daughter, I had a few complications from birth and struggled to manage my health, family life, and being the best mom I could be to my two kids. I decided that, to be the best version of myself, I needed to take the stress out of making weight. In my first three European Opens, I medalled and felt good. So from there, I continued to build more muscle to fill out the weight.
What was your experience like competing at the 2012 Summer Olympics in London?
My experience in London 2012 was great! It was amazing to be surrounded by such incredible athletes in the village. I didn’t get the result I was after, but I am glad I got to be part of the NZ team and continued to grow into the athlete I became.
Can you share the emotions and challenges you faced after losing in the first round at the 2012 Olympics?
It was tough mentally, as you work hard and train for one fight. It’s never easy to just move on, and it definitely took a while to let the whole experience sink in. I wish I had enjoyed the journey more while I was in it at the time.
How did it feel to win a silver medal at the 2014 Commonwealth Games?
This medal was bittersweet. I wanted to win so badly, and being so close was frustrating. I was quite emotional, but after taking it all in and enjoying the medal with my team, I knew it was a great way to see our hard work pay off.
What changes or improvements did you make to your training regime between the 2012 and 2014 competitions?
My coach Jason Koster ensured that we would go in more confident. We built off the experience from the Games in London 2012. As I grew older, I knew I needed to work hard if I truly wanted to make history in NZ judo.
How did it feel to win the bronze medal at the 2022 Commonwealth Games in Birmingham?
This one was special for me. Some people counted me out after having my daughter in 2018, so it was great to show them all that I was really stronger, driven, and wasn’t going to give up. Having my family there made it incredibly special to celebrate with them too.
How did your previous experiences, including the 2014 Commonwealth Games, influence your performance in 2022?
Always be willing to keep learning, no matter your age. This is really important in life. All the experiences leading up to 2022 made me more confident in my abilities.
What was your most memorable competition and why?
The Commonwealth Games in Birmingham, because having my family there to support me was so special.
How do you maintain peak physical condition for competitions?
A great strength and conditioning program and lots of Judo.
What strategies do you use to mentally prepare for matches?
I like to use visualization and shadowing. We use mental tapes for visualizations, and I find this works for me.
How do you balance the demands of training and competition with being married and raising two children?
Marriage and kids are hard, so you have to be very organized. But if you are willing to work hard towards your goals, it just makes it sweeter having the family right beside you, cheering and supporting.
What challenges have you faced in managing your athletic career alongside your responsibilities as a mother?
There is always that part of you that has mom guilt, but I find that to be the best version of myself for my family, I need to work on myself too.
How has your family’s support influenced your judo career?
My family’s support is everything. Without them, this wouldn’t be possible. They push me and make me want to be the best!
Can you share any specific instances where your family life positively impacted your judo performance?
Having my daughter made me realize how strong I really was mentally and physically. I remember one competition when my daughter was only 7 months old and crying on the side of the mat because she was hungry. I had to stay strong and focused to win the match.
Right after the fight, I went straight to breastfeeding her, and then didn’t have long to get back out there. Motherhood has no breaks, and you realize just how resilient you are.
What advice would you give to other athletes who are also parents?
You can do it! Show your kids that life with them continues as normal. They can be part of your journey as much as you are a part of theirs.
How do you manage time for rest and recovery while juggling family and training commitments?
Being very organized with time and having a good schedule. It helps that the kids are at school, so I try to fit everything in during the day and then be with them after school. We also have an amazing village—my parents-in-law are the absolute best and always on speed dial.
Have your children shown any interest in following in your footsteps in judo or any other sports?
My son has done a bit of Judo but moved on to tennis now. We are happy for him to do what he enjoys. My daughter loves Judo, so we’ll just have to wait and see.
What role does your spouse play in supporting your judo career?
My husband is my coach as well. It can be tricky at times, but I feel it has only made us stronger. He has always been my number one supporter.
What does it mean to you to represent New Zealand on the Olympic stage once again in Paris?
It’s such an incredible honour to be able to represent my country again at the Games, 12 years on. None of this would be possible without my whole TEAM on and off the mat. I hope my performance inspires them and makes them proud, knowing that their support has been instrumental in helping me get here.
Have you thought about what you want to do after you retire from competitive Judo?
Just more Judo. We have our own club, so I will continue to grow Judo in New Zealand.
What skills or lessons from judo do you think will be most valuable in your post-competition career?
Resilience and drive. Anything you believe is possible; you just have to be willing to jump all in.
What advice do you have for athletes transitioning from competitive sports to other careers?
Take your time; life isn’t a rush. Do something you enjoy!
What is the most important piece of advice you would give to young athletes aspiring to compete at an international level?
Just remember your why. Why do you love doing this? Even when it gets hard, which it will, be strong mentally and know that you got this!
