We will be travelling through the US to Mexico and would like to purchase add ons as we go. No point in adding international roaming now when we won't be in Mexico until two weeks from now. Travelling in the US until then. Also, we will need to purchase additional add on while in Mexico due to the length of our stay and again when we reenter the US to travel home.
Best answer by David AKU
Yes. It might be easiest to do it through the website / self-serve portal. Also remember you can't have two of the same Add-on active simultaneously; once the first expires, you can add the next.
Don't forget to add the free “International Voice Roaming" and / or the free “International Data Roaming” add on.