T-Mobile next month will implement a 5 GB limit on high-speed data used in Canada and Mexico by its U.S.-based customers.

The company previously allowed unlimited phone calls, texting and 4G LTE data use throughout North America on its T-Mobile ONE and Simple Choice North America plans. The calling and texting features will remain, but the company said the new data restrictions would “prevent usage beyond the intent of the product.”

Beginning Nov. 12, after 5 GB of high-speed data is used in Canada, Mexico or a combination of the two, customers will be connected at a slower 128 kbps or, with T-Mobile ONE Plus plans, 256 kbps.

The unlimited data program particularly appealed to frequent travelers to those countries, but the company said the cap would affect less than 1 percent of people currently on those plans.

T-Mobile plans to send alerts when travelers approach their data limits and when U.S. residents near the borders of those nations are roaming on Canadian or Mexican networks.

Engadget reports that T-Mobile ONE subscribers can restore unlimited LTE data by adding a One Plus International feature for another $25 per month.