OpenSignal's analysis has found that mobile connections are up to 13Mbps faster in 41 percent of the 80 countries where users have installed its smartphone app.
That's a huge change from when the first iPhone launched and when Wi-Fi was way faster everywhere and cheaper.
The speed difference varies significantly between countries. In Australia, mobile speeds average 34.6Mbps compared with Wi-Fi speeds of 21.6 Mbps, while in Lebanon mobile speeds of 14.8 Mbps beat Wi-Fi speeds of 2.5 Mbps.
In Taiwan, mobile is 1.6Mbps faster than Wi-Fi at 26.3Mbps, while Mexico-based users are getting 13.4Mbps on mobile and 11.2Mbps on Wi-Fi.
Open Signal analyst Ian Fogg argued that the findings should challenge the assumption by mobile operators and smartphone makers that Wi-Fi is better, which can be seen by phones automatically connecting to a Wi-Fi network when one is available.
While this is preferable for users with mobile data caps, it increasingly means that smartphones are automatically switching to a slower network with a worse experience.
Other countries where mobile is at least 5Mbps faster than Wi-Fi included Qatar, Oman, Greece, Czech Republic, Myanmar, Iran, Turkey, Bolivia, Croatia, South Africa, and Egypt.
Looking just at 4G speeds and not 3G, OpenSignal found that 4G is faster than Wi-Fi in 50 countries, or 63 percent of countries. Users in Lebanon, Oman, Qatar, Australia, and Greece are getting 17 to 25Mbps faster downloads on mobile than on Wi-Fi.
Still, in most places Wi-Fi remains faster than mobile, in particular the US, Singapore, and Hong Kong, due to good fixed networks.
Fogg expects that with 5G, which will eventually offer gigabit speeds, the industry will be forced to change the assumption that Wi-Fi is better.