AT&T is set to implement a policy requiring all smartphone owners to purchase a data plan for their devices. The news comes from a leaked internal memo AT&T sent to employees explaining the new policy and why it is being implemented. AT&T is using “the better customer experience” reasoning for implementing the must-have data plan policy.

“We want our customers to have the best possible experience with their Smartphones,” the company said in the memo. “A predictable bill is a key factor in customer satisfaction, so effective September 6, 2009 Smartphone customers will need to subscribe to a data plan, as the vast majority of customers already do. Data plans let customers fully utilize their device, without the worry of bill shock.”

This is one of those good news, bad news situations. Obviously the bad news is that customers will be required to buy a data plan, whether they want it or not. However, the good news is that users that purchased a smartphone without a data plan before the policy is implemented will not be required to purchase one.

AT&T has not officially confirmed the new policy yet, so we will have to wait until September to see if it is implemented.