At the end of the second quarter of 2010, more than five billion mobile subscriptions were active worldwide, according to estimates by ABI Research.
The research body said emerging markets such as India, Indonesia and China have continued to add mobile connections at a rapid clip, and showed no signs of slowing down.
According to the report, Africa led the charge, registering 4% growth in subscribers between Q1 and Q2 2010.
ABI Research vice president of forecasting Jake Saunders said Africa's low mobile penetration and usage are now attracting multinational mobile operators such as Bharti and Vodafone to the world's last remaining growth market.
"This new competition will lead to lower monthly tariffs and will allow more people on the continent to access a mobile phone," Saunders said.
The market researcher said subscriptions continued to grow in developed markets despite penetration levels greater than 100%.
The introduction of high-speed 4G data technologies such as WiMAX and LTE will ensure that subscription growth remains robust even in these hyper-saturated markets.
WiMAX has grown 91% between Q1 and Q2 2010, driven by the strong growth of operators such as Clearwire in US and UQ Communications in Japan.
Saunders said the imminent launch of LTE in the US, Japan and Europe will also ensure continued growth in mobile subscriptions over the next few years."
ABI Research expects mobile subscriptions to reach 6.4 billion by 2015, of which 169 million will be subscribed to 4G technologies.