Do I need a transit visa in Beijing ?
 

Our LH flight arrives in Terminal 3, while our international connecting flight OM to Ulaanbaatar departs from Terminal 2 some hours later.
Does this mean that we have to go through customs and passport check between T3 and T2 and therefore we need a transit visa type G ?

I can't answer your question, but I will caution you to make sure you check "official" sources and not just a board like this as helpful as fellow travelers can be.

My sister-in-law was in Mongolia last year and had to change her plans and tried to quickly fly to the U.S. via Beijing. We never got a complete, clear story from her, but she did not have the proper visa for her trip and was held up for a day with threats that she was not going to be allowed to transit. She has lived in China and speaks some Chinese, so she was able to work it all out after a day.

Thanks Kay2

I also asked the chinese embassy and also their reply was a bit confusing. They told me that if I do not have to go beyond the customs immigration I do not need a transit visa but it also depends on from which to which flight the connection is. Probably if I stayed within terminal 3 I would not need the visa but my concerns are having to go from T3 to T2. I have read also other forums on this issue and a lot of people could tranfer without a visa but as you say I would like to be 100% sure and not just 99%......

You don't need a visa if you stay in Beijing airport for under 24 hours with an ongoing ticket:

Under "Visa Free Transit":

http://www.china-embassy.org/eng/hzqz/zgqz/t84242.htm

thanks rkkwan !!

The official statement is enough clear. Do we have anyhow to pass immigration and passport check having to leave T3, maybe in separate lanes for transit passengers, where we show them our booked tickets to ULN before heading to T2 ?
Is the luggage automatically transferred from one flight in T3 to the other one in T2 or do we have to pick it up and carry it to T2 still without any transit visa ?

Good news.

Our waitlist on the non-stop flight Berlin-UB has been confirmed so this time we do not need any transit in Beijing. This post was very helpful so now I know it is possible without a transit visa within 24 hours, and within 48 hours in Shanghai Pudong !!

Thanks to all of you !!