We have an unlocked Android phone and use a pay-as-you go provider in the U.S., so it was relatively easy to get a Telcel SIM in Mexico.
From our campground outside of San Diego this past winter, we made a day trip to Tecate to get Telcel service. OXXO, one of Mexico’s convenience store chains, sold the SIM cards for about $7.50 (149 Pesos).
Before going down, we had researched a plan called “Amigo Sin Limite” which included 28 days of service with unlimited voice calls, text, and social media apps (Facebook, Instagram, Twitter, WhatsApp), and 2GB of high-speed data for less than $8 U.S. The card was easy to buy, but our limited Spanish failed to get the plan activated at the OXXO.
Great article that could save you a lot of headaches. Like the tips on a place to stay & lots of good eating.