The study conducted by market research company Frost & Sullivan found that the demand for mobile VoIP will skyrocket over the next few years.
Because of this trend it warned mobile providers not to resist making VoIP available to its customers.
Market analyst Saverio Romeo said: "70% of the top European mobile providers restrict access to VoIP. These operators are continuing to discourage subscribers from using VoIP despite the fact that there is a high user demand for such a cost effective service."
Romeo added that this didn't make sense as many mobile platforms supported Session Initiation Protocol for third party apps. Meanwhile phone companies could provide benefits such as High Definition voice which VoIP companies like Skype might not be able to.
This demand will be fuelled by the increased availability of broadband, smartphones and flexible pricing as well as the success of iPhone apps which are convincing other smartphone makers to create phone apps.
In 2008 Europe, Asia, North America, and Latin America were responsible for $605.8 million of mobile VoIP revenue. By 2015 that revenue will reach a staggering $29.57 billion.