New research from wi-fi provider iPass suggests there will be 47.7 million public hotspots worldwide by the end of 2014.
France currently has the most hotspots, followed by the US and UK.
Hotspots are designed to fill the gaps in coverage left by mobile networks and are often offered free of charge.
The study is one of the first comprehensive looks at the distribution of global wi-fi. A clickable map of hotspots around the world shows the numbers in each region and where they are located - in homes, on trains, planes, airports and retail outlets.
Over the next four years, global hotspot numbers will grow to more than 340 million, the equivalent of one wi-fi hotspot for every 20 people on earth, the research finds.
But this growth will not be evenly distributed. While in North America there will be one hotspot for every four people by 2018, in Africa it will be one for every 408.
While Europe currently has the most dense wi-fi coverage, Asia will overtake it by 2018, according to the report.
The research suggests that the vast majority of hotspots - nearly 34 million - are in homes. These hotspots are part of a growing trend to extend home wi-fi to the local community.