Every line has a date

Lupita sells tamales from a stall in Iztapalapa and takes orders on WhatsApp. Her prepaid number ends in 8, so she has until 15 December. She has seen the adverts. She tried once, on her phone, between customers: the form took a photo of her ID, then asked for a selfie the camera would not accept in the light of the stall. She meant to try again. Lupita is a composite, drawn from customers like her.

Since 9 January 2026, every mobile line in Mexico has to be linked to its holder’s CURP, the national population registry code. The first deadline, 30 June, was extended into a calendar by the last digit of the number, starting with lines ending in 0 on 15 August. Four dates remain: lines ending in 6 by 15 November, 7 by 30 November, 8 by 15 December and 9 by 31 December.

By 2 November more than 100 million lines had been linked, 83.3% of the about 120 million that the CRT, the telecoms regulator, expects by the end of the year. That target already leaves out about 25 million lines the CRT expects to purge as unused, many of them promotional SIM cards that were never activated.

Missing a date has a precise consequence. Within 72 hours the operator suspends the line. A suspended line can still call emergency services, receive government alerts and reach the operator to finish the registration, and nothing else. Service comes back as soon as the customer links the line.

Many customers have taken that route. After the first deadline, for lines ending in 0, the CRT reported 2,353,453 lines reactivated after linking, and expected about 2.6 million more in the following days. For lines ending in 3, 1,213,717 had been reactivated by early October. Each of those is a customer who lost service first and registered after.

Not everyone comes back. AT&T Mexico lost 668,000 prepaid users between April and June and said the decline was expected because of the linking process. The CIU, a telecoms consultancy, counts 162 million active lines in December 2025 and 157.1 million in June 2026, with most of the drop in prepaid.

For an operator, this is unusual. Churn normally arrives unannounced. Here every operator knows, line by line, which customers have not linked yet, and the day each of those lines will be cut. It can see where its own registration flow loses people: at the ID photo, at the selfie, at the CURP check. It can see which customers came back after a suspension and which did not. It will rarely face a churn event this easy to predict.

It is also a contact with millions of prepaid customers within a few months. Many of them hear from their operator only about top-ups and offers. This time the operator is asking them to do something, under a deadline, with their identity documents. How that goes will colour what they think of the operator for a long time after the registry closes.

Treating it as a customer journey means three things. Measure the registration like a sale: where people start, where they stop, how long it takes, which step sends them to a shop. Contact the customers still missing before their date, in the channel they use, with help rather than reminders: a shop that will do it with them, a time slot, an answer when the selfie fails. And treat every reactivation as a recovery: the customer has just lost service, and the weeks after decide whether they top up again.

For Lupita the difference is concrete. A message in November that says her line will be cut after 15 December, and that the shop two streets away will do the registration with her in ten minutes, keeps a customer. A suspended line in the busiest week of her year loses one. Lines ending in 6, 7, 8 and 9 still have their dates ahead. Operators still have time to make them easy.