The survey found on average that smartphone users who pay for cellular plans still use Wi-Fi about a third of the time. In two years, Cisco expects that smartphone users will access Wi-Fi about half of the time, with the other 50% spent accessing via cellular.

Cisco also found that about half of tablet, laptop and e-readers users already connect exclusively through Wi-Fi already. "Given a choice, more than 80% of tablet, laptop and e-reader owners would either prefer Wi-Fi to [cellular] access, or have no preference," the survey said.

Cellular providers have come to realize that Wi-Fi can be a supplement to their networks, especially when they are crowded, Taylor said. Emerging standards, such as Hotspot 2.0, also called PassPoint, will make authentication of smartphones entering Wi-Fi zones simpler.

"There's a real push in the retail environment to offer Wi-Fi," Taylor said. Some retailers have begun to notice that shoppers carry smartphones and other mobile devices, which can supply information on sales and directions around the store rather than having to rely on stationary kiosks that take up store space and can be costly.

In general, Taylor said the survey shows that Wi-Fi is a "viable competitor" to cellular networks. As carriers introduce limits on cellular data plans, Wi-Fi could become even more valuable.