After his career he became water polo coach of the Netherlands women's national water polo team. First as an assistant to head coach Robin van Galen who coached the team to Olympic gold in 2008. After Havenga took over as head coach, the team won silver at the 2015 World Aquatics Championships and two silver medals at the European championships of 2014 and 2016. However, at the Qualification tournament of the 2016 Summer Olympics in own country, the team was not able to qualify for the 2016 Summer Olympics.