Millicom operates in nine Latin American markets, including Bolivia, Colombia, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, Panama and Paraguay.

The firm took over paging company Meta Systems in October 1982 and then raised $9 million in its first round of financing, managed by chief executive officer, Orhan Sadik-Khan and Kevin Kimberlin.

To enable Millicom to earn its 10% royalty from Racal-Millicom, a controlling shareholder, Stenbeck commissioned a startup with three employees, Technophone, to develop the world's first pocket-sized mobile phone.

[11] Highlighting its plans to offer the Voice and Data phone (predecessor to the smartphone), his Racal-Millicom joint-venture was renamed Vodafone.

[14] In December 1989, Millicom set up Microtel Communications Ltd. by teaming up with Pacific Telesis and British Aerospace (later bought out by Hutchison Telecom.

)[15] Microtel was awarded a personal communication network (PCN) license to compete with Vodafone in the United Kingdom, a service launched on 28 April 1994 under its brand name, Orange.

In 2008, Millicom acquired AMNET for fixed Internet and TV services, leading to the company's formal cable business entrance.

In 2016, Millicom partnered with Microsoft to provide cloud services to its Tigo Business customers in eight markets in Latin America.

In 2017, Millicom launched TIGO ONEtv, the first Next Generation TV (NGTV) service for LATAM customers, integrating traditional linear television content with over-the-top platforms, as well as video on-demand.

[29][30][31][32] In 2019, Millicom expanded its Latin American presence, acquiring subsidiaries of Telefónica in Central America (Panama and Nicaragua).

[33][34] In addition, in 2019, Millicom common shares started trading on the NASDAQ Stock Market in the United States under the symbol TIGO.

[41][42] In 2023, Apollo Global Management and Marcelo Claure held discussions with Millicom regarding a potential acquisition of all outstanding shares of the company.

This appointment introduced a new management style to the group: significant headcount reductions, lower capital expenditure, standardization of network and frequency usage charges.

It owns a 100% equity interest in the operation after acquiring the remaining 45% stake from its local joint venture partner in an $2.2 billion deal in November 2021.

Tigo Guatemala is the country's largest mobile operator with more than nine million customers and market share of 53.4 percent.

Telenovelas broadcast on Tigo SAT Network Unicanal was a 24-hour Pay TV cable purchased in October 2012 by the merger with Cablevision Paraguay (property of Grupo Clarin Argentina).

In February 2015, Tigo sold the operations of Unicanal to JBB Group, a company owner of Radio Disney, specialized in media, entertainment, distribution and in real estate.

[52][citation needed] Tigo Costa Rica is the country's leading pay TV operator with more than 30 years of service under different brand names dating back to Millicom's acquisition of Amnet in 2008.

[57] As of March 2021, Millicom maintains operations across nine Latin American countries: Bolivia, Colombia, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, Panama and Paraguay.

[58] Millicom (TIGO) previously held operations in Chad, Democratic Republic of the Congo, Ghana, Mauritius, Rwanda, Senegal, Sierra Leone, and Tanzania.