This post is based on our experience crossing the border from Erenhot (China) to Zamiin-Uud (Mongolia) in May 2024. There are two typical ways to do this border-crossing. You can take the Trans-Siberian train from Beijing to Ulaanbaatar. Or, you can string the journey together with a bus on one side of the border, and then a train. So, if you ever wondered how to cross the border between China and Mongolia by road, then read on.