Originally Posted by
Swanhunter
Yes and I have heard of people being denied boarding without a transit visa. The common customs and immigration zone means arrival in Moscow is where you will clear immigration for all 3 countries. If you fly back via Moscow you will need a double entry transit visa and have the novelty of visiting Kazakhstan without actually clearing immigration there. Think of it as Schenhen with visas and hassles.
N.B if you need a visa for Kakhstan you should still get one as it will be needed for internal hotel/travel purposes.
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.