score:7
This will depend very much on the details, i.e. which countries, which citizenship(s) and which border crossing.
But yes, at many land border crossings, you can swap passports. Often a land border crossing consists of two separate control points: exit from country A which is staffed by country A and governed by country A jurisdiction (laws and regulations) and an entry point into country B which is fully governed by B. In between is often a short walk or drive of "no mans land".
In many cases you can use one passport to exit A and a different passport to enter B.
Example: On Thursday night I crossed from China into Hong Kong at the Shenzhen land border. I left China using my US passport (which has a China visa and is the one I used to enter China). Entering Hong Kong I had the choice to use either on my US or German passport. Either one would have worked and the choice is independent on how I left China. These are different control points staffed by different people with different rules and different forms to fill out.
Upvote:4
Sometimes they will not allow it. I tried to leave Cambodia to enter Thailand and they would not allow me to use a different passport to enter Thailand from the one I used to leave Cambodia. This is ridiculous but the truth is the Thai staff at the Hat Lek border simply do not understand the law. At an airport there is never an issue but there is at a land border at times.