Carriers often try to attract switchers and new subscribers during new iPhone season, and AT&T is doing its part today by upgrading its mobile plans with some modest data upgrades at reduced costs. AT&T is also announcing that its new plans no longer include overage charges for exceeding data caps. AT&T subscribers won’t automatically be moved to these new plans, so current customers will want to compare these new rates and potentially save money with more data.

AT&T’s current mobile data packages introduced last year in part include 2GB/$30, 5GB/$50, 15GB/$100, 20GB/$140, 25GB/$175, and 30GB/$225 tiers. The new plans will offer different tiers including 1GB/$30, 3GB/$40, 6GB/$60, 10GB/$80, 16GB/$90, 25GB/$110, and 30GB/$135.

Overage charges on the previous plans included a $15/1GB charge after using rollover data. AT&T says its new plans will remove overage charges and instead drop customer data speeds to as low as 2G when a data allotment is used up. AT&T notes that unlike other carriers, it doesn’t charge customers for this benefit. Verizon charges $5/month for its similar ‘Safety Mode’ feature on 2GB, 4GB, and 8GB plans.

Other features from current mobile share plans and the new options introduced today like unlimited talk and text, mobile hotspot, and rollover data will stick around.

While the plan changes are modest, they are worth checking out especially if you’re already an AT&T subscriber. For example, my 15GB/$100 plan can be changed to $16GB/$90 which adds an extra 1GB of data for $10 less a month. [Update: Compare your plans before changing as the device cost actually makes the 1GB increase $10 more/month for my four-lines account.]  The previous jump from 5GB to 15GB left customers that used more than 5GB but less than 15GB paying twice as much for data access, too, so the new 6GB and 10GB plans may be better options.

Earlier this year, AT&T introduced new unlimited data plans and simplified its ‘Next’ upgrade program with two options: Next for upgrading every 24 months, and Next Every Year for upgrading every 12 months.

The new plans will be available on August 21. Additional details are available on AT&T’s website.