I arrived in Switzerland in May 2008, and received a letter about the mandatory health insurance not so long after. I had 3 months to either get myself a Swiss health insurance, or prove that I already had one that covered me while being in Switzerland.

I am still registered in Holland, and therefore also obliged to have a health insurance (like it is here). The one I have includes worldwide covery, so I sent in a copy of my European health insurance card, etcetera.

Recently I received another letter asking for proof again (this time from the government, instead of the city of Zürich), but this time including a form that needed to be filled in by my Dutch health insurer. This is a mission impossible (once send, I'm sure I will never get back a filled in form), so I sent them even more proof (copy of the policy), but without the filled in form. Fingers crossed...