AT&T's GoPhone data plan has received a boost, doubling the previous data transfer amounts at the same prices. The changes will take effect on April 22.

The deal will be available to customers on the $50 Unlimited Data Talk & Text plan, or the $25 Unlimited Text/250 minutes nationwide voice plans, AT&T said in a press release. The changes are 10MB (up from 5MB) for $5, while $15 and $25 get 200MB (up from 100MB) and 1GB (up from 500MB) respectively. 1GB should be enough to handle e-mail, Facebook (and other social networks), Internet browsing and send a couple of photos per month.

The data plans are also available as add-ons to the $50 unlimited data talk and text plan, along with the $25 unlimited text plan with 250 minutes talk time.

Contract users on AT&T get 3GB of data for $30, just $5 more and an average $10 per gigabyte.

While that's good news, there's a catch: GoPhone users who want data have to switch to one of the above plans from April 22. As The Verge reported, it was previously possible to use prepaid data packages while using a phone on pay as you go for talk time. That won't be available.

Verizon offer a $30 monthly unlimited data plan for prepaid customers, while Virgin Mobile offers the same with 300 minutes of talk time for $35 a month. T-Mobile offer unlimited talk, text and data for $50 a month.

AT&T is aiming to compete with carriers such as Sprint and Leap Wireless International who offer low-cost options. Prepaid plans are attractive because customers are free from two-year contracts.

Whether customers are looking to switch is unknown, but data usage has increased in recent years as data has become faster to use, thanks to 4G LTE network.

Prepaid is still attractive for some users, as high-end devices can be bought while using plans that are similar to those on contract.

AT&T launched its first prepaid Android smartphone last year, the LG Thrive. AT&T currently offers around 10 smartphones on Android, including the Samsung Captivate and Double Time devices.

(reported by Jonathan Charles, edited by Dave Clark)