1/2 fare car usage - start date

I will be purchase a 15 day combi flex pass with the 1/2 fare card included

My question is: Can I use the 1/2 fare card first or must I first activate the pass first and use it?

Since I will be staying in Interlaken for a month, I would like to take some local bus or train trips and use the 1/2 cards prior to using the pass for longer day trips.

Hi connestee712,

The pass must be activated first. Then you'll need to use the first free travel day. The half fare card is valid between the first and last free travel day. If that does not suit your plans you can buy a regular Swiss Travel Pass Flex and a separate Swiss Half Fare Card. It's explained here. For prices, please look here (and select the Combi pass if applicable).