I have to travel from Mexico to Japan with a layover in the US.
I will take an plane from Mexico City to Dallas, and after 4 hours, I have a flight to Tokyo.
What do I need to present to US immigration when entering the US from Mexico, besides my US visa and my Mexican passport?
You’ll need to make a customs declaration, whether at an automated passport control kiosk or by presenting a blue customs declaration form. The officer might ask to see your ticket or, if you have it, your boarding pass. Other than that, no additional document is likely to be required.