Brazil's main telecommunications companies are:
- Vivo (Telefónica): Telefônica Brasil S.A. started its operations in Brazil in 1998 after acquiring part of the telephone companies privatized at the time, providing fixed services. In 2002, Telefónica Spain and Portugal Telecom formed a joint venture for the provision of mobile services under the brand "Vivo." After acquiring Portugal Telecom share in 2010, Telefónica's Brazilian subsidiary became Vivo's parent company. In 2012, all of its services provided to the end-user, fixed and mobile, were integrated under the Vivo brand. Telefônica Brasil S.A. counted with more than 95 million customers at the end of 2018, with 73 million customers in the mobile operation and 22 million customers in fixed operation. It is the leader in the mobile market and the second-largest company in the fixed broadband market. Globally, Telefónica provides services in more than 10 countries in Europe and Latin America.
- Claro: Claro S.A is a subsidiary of América Móvil, a major telecommunication group in Latin America. It also provides services in the U.S., Austria, and Eastern Europe. Claro operates in 17 countries and has more than 290 million mobile phone customers. Claro S.A. was established in Brazil in 2003 and it has consolidated its operation in the early years through the acquisition of other seven regional mobile companies. It is the second-largest mobile operator in Brazil, with almost 25% of the market. In 2019, Claro completed the incorporation of the company NET, the former cable TV and fixed broadband operator of America Móvil's group in Brazil. By then, NET was present in more than 200 major cities and metropolitan regions in the country. Currently, Claro is the leader of the fixed broadband market, with almost 30% of the marketplace.
- Nextel: Nextel Telecomunicações is the Brazilian subsidiary of NII Holdings, Inc, a mobile communications services company headquartered in Reston, Virginia (USA). In Brazil, Nextel operations began in 1997 with radio system push-to-talk services, and as of 2010, the company was authorized to provide mobile phone services. In March 2019, América Móvil, announced the acquisition of Nextel's operations in Brazil. The operation was approved by the country's antitrust authority (Cade) in September of the same year and it is under an analysis of the telecommunications regulatory body (Anatel).
- Oi: Oi Group was formed from Telemar, one of the fixed-line companies privatized in 1998. Regarding its market share, it is the third-largest fixed broadband operator and the fourth-largest mobile service provider in Brazil. Its headquarters are in Rio de Janeiro, Brazil. In 2014, Oi was merged with Portugal Telecom, but ended up selling PT assets to the Altice Group in 2015 due to financial issues. In 2016, the group requested judicial rehabilitation to avoid bankruptcy.
- TIM: TIM Participações S.A. is a company controlled by TIM Brasil Serviços e Participações S.A., a subsidiary of the Telecom Italia group. Through its subsidiaries, TIM Celular S.A. and Intelig Telecom Ltda, the group operates in the mobile and fixed telephony markets as well as in the provision of long-distance, data transmission, and internet services. It is the third-largest company in the mobile service market.
- Algar: Algar Telecom is a smaller Brazilian telecommunications company operating in more than 350 cities in the states of Alagoas, Ceará, Espírito Santo, Goiás, Mato Grosso do Sul, Minas Gerais, Paraíba, Paraná, Rio de Janeiro, Rio Grande do Norte, Rio Grande do Sul, Santa Catarina, São Paulo, and Sergipe, as well as the Federal District. The company is based in Uberlândia (Minas Gerais).
- SKY: SKY is the second-largest pay-TV company in share in Brazil and a smaller fixed broadband provider. In 2006, the merger between SKY and DIRECTV was consolidated and, in 2015, AT&T completed the acquisition of DIRECTV. Currently, SKY is controlled by the DIRECTV group—a subsidiary of AT&T—and has small participation of the Globo group, which is Brazil's main media corporation.