Snowden received his passport and swore an oath to become a Russian citizen at a ceremony on Thursday, about three months after Russian President Vladimir Putin promised him Russian citizenship.
It was unknown if he renounced his US citizenship.
However, the US revoked his US passport in 2013.
Snowden was in Hong Kong when the revelations broke.
He was stranded in Moscow on a planned trip to Ecuador where he intended to seek asylum.
Snowden remained in Russia, where he married American citizen Lindsay Mills.
The couple has two children.