A new study published yesterday by the NPD Group’s Connected Intelligence shows a strong preference among tablet users to connect their devices to the internet via wifi instead of cellular data connections. The study shows that close to 65% of tablet users connect via wifi only, while a substantially lower number connect using a mixture of wifi and cellular data, or cellular data only

This contrasts with the data gathered in the spring of 2011, which showed that while 60% of users used wifi only, 5% of those planned to add cellular data packages. Instead cellular data use has declined by 5% overall in the intervening six months, as the number of wifi-only users has increased, rather than decreased.

While most tablet devices include the ability to connect to 3G data networks – at least as an optional feature, as with Apple’s iPad – using these cellular networks comes with an extra cost. First, devices capable of accessing cellular data networks are generally more expensive – the iPad 3G is a whopping $130 more expensive than the wifi only model. Second, 3G data plans carry a cost, ranging from $15 a month (on AT&T’s cheapest plan) to $80 per month (on Verizon’s most expensive plan). On the other hand, wifi-only devices tend to be cheaper, and accessing wifi networks – which are fast becoming more ubiquitous – is generally free, unless you’re in a fancy hotel or an airport. The simplest explanation for the popularity of wifi over cellular data, then, is cost. Many people are apparently finding that the convenience of being able to access the internet anywhere they have a 3G connection is not worth paying what tablet makers and carriers demand for it.