I am pretty sure I will be getting a 6 day Bernese Oberland Regional Swiss Pass. Does it count a "day" as a 24 hr period from when i begin to use it, or a set day 5am to 5am?
It's not 24 hours from when you first use it.
Most Swiss travel passes, and I think the BO Pass would be the same, operate on a travel day being 29 hours starting at 00:00am and finishing at 05:00am the next day. Any travel on the second day has to be completed by 5:00am but that is unlikely to be an issue with a BO Pass.
Rockoyster is correct but I like wording it like this: Buy a 6 day rail pass starting June 1 (doesn't have start time) and it expires 05:00 on June 7. :)
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