Opera is the world's number one mobile browser, overtaking the Apple iPhone's Safari browser in May 2009 - according to data from StatCounter Global Stats.
However, if one includes Apple's iPod touch then its Safari browser still leads with the iPod touch alone taking 14.9 percent of the market in May. The iPod touch is effectively an iPhone without the phone and camera.
StatCounter, which provides free website traffic analysis, is one of the largest web analytics companies, recording in excess of ten billion pageloads per month.
In March it launched StatCounter Global Stats, a free online service that captures market share of search engines, browsers and operating systems including mobile.
"Opera began the year in the number one slot but iPhone overtook it in February. May saw Opera regain the number one position," commented Aodhan Cullen, CEO and founder of StatCounter. "It will be fascinating to watch how this battle plays out over the year."
He drew attention to the performance of the BlackBerry smartphone, which is in fourth place with 6.9 percent of the global market.
"An interesting finding is that BlackBerry has steadily increased market share from 4.9 percent in January to 6.9 percent in May. Despite the global recession it looks as if executives are holding on to their BlackBerries," commented Cullen.