Brazil and Mexico account for most mobile app sessions in Latin America, according to data for the year leading up to June 2016.

According to mobile analytics and advertising firm Flurry, 34% of app sessions on its platform in Latin America between June 2015 and June 2016 occurred in Brazil, notably more than any other country in the region. Mexico ranked second, with about one in five app sessions, for a total of 55% of app sessions in Latin America’s two largest markets.
In third place, Argentina was home to just 8% of mobile app sessions.
These figures are generally in line with the overall size of Latin American mobile phone markets. eMarketer estimates that this year, 64.0 million people in Brazil will use smartphones, making up about 33.8% of the smartphone population of Latin America. Mexico, meanwhile, will be home to 44.2 million smartphone users this year—about 23.3% of the total in the region.
eMarketer estimates Argentina is the No. 4 smartphone market in the region, with around 9% of users, just behind Colombia, which has about 10% of the total.
So how exactly do mobile users in Brazil tend to spend their app sessions? Earlier research from Flurry, from August 2015, reveals that nearly half of the time users in Brazil were on mobile apps, they were using utility and productivity programs.

About 20% of time spent was devoted to sports, and nearly 20% was devoted to messaging and social.
An eMarketer forecast from November 2015 projects that Brazil's dominance in mobile apps—specifically messaging apps in this case—will continue, growing by nearly 10 million from 2016 to 2017. eMarketer predicts a total of 56.5 million mobile messaging app users in 2016.
By 2017, there will be 64.5 million, a 14.2% change, slightly higher than the regional growth rate.