Originally Posted by
bnurkhai
Post above already said this, but this info is false. Belarus, Kazakshtan and Russia don't have an open border policy like the Schengen, it's just a customs union atm no immigration. You don't need a visa to visit Kaz, you do need a visa if visiting Russia, idk about Belarus. There is no unified visa for all three countries.
Good point about Kazakhstan, however Russia and Belarus are a common immigration zone in that there are no controls at the border. You do need the relevant visa for hotel check in, registration etc. When I travelled the Trans-Sib I was stamped into Belarus at Brest and only received a Russian exit stamp at Nauskhki.