Norwegian browser maker Opera has significantly boosted its visibility and usage worldwide, after it agreed deals with two of the world’s largest global mobile operators: India’s Bharti Airtel and Latin American telecom giant America Movil – which boast nearly 500 million subscribers combined.

The partnerships will see both carriers promote a customized and co-branded version of the Opera Mini mobile browser to their subscribers, leaving the browser set to gain traction among Bharti Airtel’s 253 million customers and America Movil’s 242 million.

The Airtel deal is particularly significant for Africa, where the India-based operator is active in 17 markets, serving more than 50 million customers and holding 12 3G licenses. Additionally, Opera will gain visibility within its three markets in Asia, including India where it has close to 183 million subscribers.

America Movil serves 18 countries in Latin America and is particularly strong in Mexico (more than 70 million customers) and Brazil (47 million). The Mexico-headquartered organisation is ranked as the world’s fifth largest carrier, based on global customer numbers, while Bharti Airtel is third.

Latin America, Asia and Africa are three key markets for mobile Internet growth, with India, in particular, set to see mobile access overtake fixed-line usage before the end of the year.

The Opera Mini series is well known for its compression technology which allows pre-paid users to enjoy more time online, and gives feature phone owners a more sophisticated and customised Web experience.

Opera Mini 7 was launched last week, and the latest release provides a more social-centric experience for users, thanks primarily to a smart page that provides updates from Facebook, Twitter and other services and sites in one place.

Opera has agreements with 13 of the world’s top 30 operators, and it claims that its Opera mini series is used by more than 168 million mobile phone owners worldwide. Emerging markets are a particular strength for the company, and it boasted the title of the world’s most used mobile browser until Android Robot overtook it earlier this year.

The Norwegian company’s strong reach and intimate knowledge of the mobile Web has reportedly made it an acquisition target for Facebook. The social network is said to be one of two firms engaged in negotiations to buy Opera, according to sources, although neither company has confirmed the speculation.