AT&T has raised the cost of its data plans for smartphones and tablets and given a slight bump to data plan caps, with the new rates going into effect Sunday Jan. 22.

AT&T and chief rival Verizon Wireless used to offer unlimited data plans for their smartphones, but both have steadily moved away from those types of plans in the past few years. But as more customers pick up data-sucking iPhones, iPads, Android devices and Windows Phones, the networks get more bogged down and cost more to operate.

“Customers are using more data than ever before,” David Christopher, chief marketing officer for AT&T Mobility, said in a statement. “Our new plans are driven by this increasing demand in a highly competitive environment and continue to deliver a great value to customers.”

AT&T requires its smartphone owners to have a data plan, and current customers pay $15 for 200MB per month or $25 for 2GB per month. The least-expensive plan will now be a $20 plan for 300MB of data per month. The next-highest plan will be $30 for 3GB of data per month.

The new prices will only effect new customers, but existing customers can change to these data plans if they choose. I, for one, will be sticking with my current data plan because I already find my bill too expensive.

The company’s three smartphone data plans will now be:

• AT&T DataPlus 300MB: $20 for 300MB
• AT&T DataPro 3GB: $30 for 3GB
• AT&T DataPro 5GB: $50 for 5GB, with mobile hotspot / tethering

And its tablet data pricing has changed to:

• AT&T DataConnect 250MB: $15 for 250MB
• AT&T DataConnect 3GB: $30 for 3GB
• AT&T DataConnect 5GB: $50 for 5GB

What do you think of the new pricing?