If you thought Verizon was immune to tiered data plans on its 3G network, think again. Verizon CEO Ivan Seidenberg told investors on Thursday that the company was preparing to roll out new plans within the next four to six months, with limits on different tiers depending on how much data customers want to use. This definitely looks like the future of 3G data pricing, though 4G plans will likely remain limitless—at least until a critical mass of customers get on board.

Verizon's comments follow AT&T's decision to ditch its unlimited 3G data plan earlier this year. Though current customers can continue to milk their $30 monthly unlimited plans for as long as they continue to use the same device on the same account, the new plans have 200MB and 2GB limits for $15 and $25 per month, respectively. AT&T argued that the new plans were a way to introduce lower data pricing and make it accessible to more customers, but heavy data users were quick to note that the price per gigabyte was quickly skyrocketing. (Sprint also caps its 3G network usage at 5GB per month.)

Seidenberg implied that Verizon's plans would differ from AT&T's—"We're not sure we agree yet with how they valued the data," he was quoted saying by the Wall Street Journal. However, he didn't provide any real details about what the Verizon plans would look like.

It's not surprising that Verizon will begin shifting towards tiered data plans. A recent report from Validas said that Verizon's 3G users gobbled the most data out of all US cell network users. More and more customers are making the switch from traditional feature phones to smartphone-like devices that use 3G, and as a result, congestion on 3G networks continues to build.

This has not yet been the case for 4G networks, though. Sprint and its partner Clearwire have so far left their 4G/WiMAX network open for the pillaging, with the average user downloading around 7GB of data per month. Sprint said the reason it's currently letting users have unlimited 4G data is because it doesn't want consumers to have to change their behavior—yet—and it also wants to attract new customers leery of 3G caps.

This will likely be the plan for when Verizon and AT&T roll out their 4G/LTE networks as well. New customers are key, and as long as the network remains relatively unsaturated, the carriers know that unlimited plans are still more attractive to customers than limited ones. Sprint VP of 4G Todd Rowley did point out, however, that if the average data use on its 4G network skyrockets to something like 20GB per month, the company might be forced to cap 4G data usage.

For now, though, it looks like the future of 3G data plans includes tiers, while 4G data plans will remain unleashed.