A few years ago I got into traithlons in the UK and competed in a few. It was a great thing to train for and gave me so much satification when I finished all three legs of the event.
When I came to switzerland I also wanted to get back into these and started looking for events to do. At first I did not know where to look but a website that is great foa ll sporting events in Switzerland is Datasport.ch . This website has running races, swimming, mountain biking and triathlons on it and also lists many international events as well.
From here I found the three Lake Geneva events that take place in quick succession each year. There is the International Triahtlon of Geneva, followed three weeks later by the Triathlon of Nyon and then a further two weeks later is the Traithlon of Lausanne. All three events are very well put on, with closed roads and lake swims. The websites and information for each can also be found in english and they cater well for the international community coming over to compete in these events.
When entering all of these events you do need to have either a day license or a year license to be able to race but these can either be purchased at entry, or on the day.
There are also plenty of traithlon clubs in the region that you can join for training help and motivation and the membership of these often includes a license.
Enjoy your traithlons and let me know if you are going to be racing in any of them this year or in coming years.