Originally Posted by
MSPeconomist
Aren't foreigners required to carry passports in Russia?
Technically no (neither are locals), but you can get detained for hours without an ID. However for an US or EU citizen carrying a photocopy of the passport and the Russian visa may be enough - the police will not be interested in you unless they have a genuine reason for it.
ADD: Not sure if it applies to foreigners, but age matters: when I was 25, I got my docs checked at least once a month. I'm 35 now and the last time the police asked for my passport several years ago. YMMW