USA Mexico border crossings
 

Anyone happen to know if on a USA B2 tourist visa it is possible to cross the Mexican border into the USA more than once on the same visa? I'm a uk citizen btw. I'll be in the USA to begin with and need to cross at least twice.

Many thanks in advance.

Crossing into Mexico or Canada and back multiple times is not a problem, but for Mexico you need to get a FMM (tourist visas) at the border if you move more than a couple of miles south of the border. (not sure if the FMM is multiple entry but it is for 180 days and doesn't have to be handed in at the border when leaving so probably will be multiple entry.
TIP for a vehicle is also required once you leave BAJA or the hassle-free area.

However, the USA counts any time you spend in Mexico or Canada as part of the allowance you get under your USA visa - 180 days for B1B2. It doesn't reset by crossing the border out of the USA. Since you are starting in the USA then the 180 days includes all time in north America until the time you leave the USA for the last time by flying out or by heading south into central america.

Thanks for the info Tony- very helpful.