What is the best way to obtain visas for the Trans-Siberian/Trans-Mongolian Railway?

As I know, in Russia visas can be achieved in two ways:

1. By invitation from some people or company in Russia, and I think this is not for you, because it is not very stable way to get visa.
2. For a touristic trip or voucher. This can be made by some travel agencies. Try to choose a popular one like: ???? ?????? ???????
3. Also in some cities you can stay for three days without visa, but this is not for you, I think.

Standard fee for the touristic visa is 70 euro. If you have an invitation, you will get your visa in 2-3 working days.

I was looking into the same journey recently and the best resource I found was seat61 http://www.seat61.com/Trans-Siberian.htm#Visas

I talked to one of the agencies they recommend http://www.realrussia.co.uk/ They knew what they were doing, they quickly responded and sent us quotes and paperwork for both my husband and I (Australian and English passports).

For the record, it is not necessary to go through an agency to obtain your visas, I've just completed the full troika of Russia, Mongolia & China and every application I made was accepted the first time around. You do need to get started several months in advance though!

Some personal notes, although the details will vary based on your citizenship and where you apply: this is all for an Australian applying in Australia. Also, despite minor differences in the requirements on paper, standard Australian passport photos were fine for all three.

• Russia: This is the most complicated by a long shot, so get this one first. I applied in person at the Russian consulate in Sydney, using the detailed step-by-step guide here, which was extremely helpful. Cost A$135, processing time two weeks plus wait for appointment. Two additional tips:

  1. Apply for your visa appointment well in advance, since it may take a few weeks to find a free slot.

  2. When requesting your letter of invitation (I used ivisa.ru), get one that covers the entire length of your stay plus some buffer and use the same dates on your visa application. I naively only got one for the days I was actually staying in a hotel (as opposed to sleeping on a train), so the dates on the visa application were different, and was grilled about the discrepancy. They accepted my explanation, but you may not be so lucky.

• China: Applied at the Visa Center in Sydney, which is extremely efficient. You will likely be asked for proof of how you will enter and depart China, so bring along train/flight tickets or reservations. I also had an itinerary from a tour agency in China, which is not strictly necessary (and, sotto voce, doesn't match my actual itinerary), but it was sufficient to cover all other documentation needs. Appointments are required but are usually available next day. Cost A$109.50, processing time four business days.

• Mongolia: Applied via post at the Mongolian Embassy in Canberra. The documentation and travellers' reports are not clear on whether you need to include train tickets for a tourist visa, but I called them up and was told that a "tourist agency itinerary" was enough. I sent along my ticket reservation receipts (not an actual ticket) and that was good enough. Also, Russia & China take credit cards but Mongolia insists on a bank cheque, so order that at least a week in advance. Cost A$230 (!), processing time 4 days.

  • Transit visas are cheaper (A$150) but have tighter documentation requirements ("Detailed travel program provided by the Tour agency"), so I played it safe.

Elapsed time: I started my paperwork on April 21st and received my final visa on May 31st, so around 40 days end to end. I could have shaved a week off this by booking my Russian visa appt earlier, another week by paying for express processing for Russia & China (not available for Mongolia), and a few days by paying for express mail to/from the Mongolian Embassy.

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Update: I've extended the answer above into a lengthy blog post with more detail.