AT&T’s new sharing plans optional, undercut Verizon on price

AT&T(s t) revealed the shared data plans it’s been hinting at for so long. The new pricing structure looks very similar to the shared tiers Verizon announced last month, charging a per-line rate for each device, bundling in unlimited voice and SMS and offering a flat fee for buckets of common data. There are two key differences though: AT&T’s plans are optional for new and existing customers, and they’re slightly cheaper.

Verizon’s(s vz) structure is pretty simple. Pay a per-device monthly fee ranging from $10 for a tablet to $40 for a smartphone and then buy a bucket of data starting at $50 for 1 GB and going up to $100 for 10 GB. AT&T, however, is using a sliding scale to determine the amount your charged for each smartphone. For instance a family buying a 1 GB plan would pay $45 per smartphone connected, while the same family would pay only $40 per phone if they signed up for a 4 GB plan.

In general, the prices AT&T charges for the actual data buckets start off cheaper than Verizon’s equivalents, but as you get into the upper tiers, Verizon starts offering better volume discounts. For instance at 6 GB, Verizon charges $80 while AT&T charges $90. But at that tier AT&T is charging a $35 per-device fee. So four smartphones sharing 6 GB plans costs roughly $230 a month, while the same setup on Verizon costs $240. If you move down to two smartphones sharing 6 GB though, both carriers’ prices wind up being the same, $160.

Both carriers are charging the same rates for connecting non-smartphone devices and customer overages are being billed at the same rate: $15 per gigabyte. The new Mobile Share plans will be available in late August.

The biggest shocker is that AT&T is making these plans strictly optional – and not just for existing customers. New customers can still sign up for the revised individual data plans AT&T implemented in January – which in the case of individual customers could wind up being the cheaper option by far. And don’t worry, unlimited customers, your plans remained grandfathered.