While Sprint continues — for now — to offer smartphone users unlimited data plans without overage charges or throttling, the company has announced that customers with unlimited 4G plans for mobile broadband and mobile hotspot devices will have very definite limits starting in November.

Currently, Sprint mobile broadband customers have choices of plans that offer unlimited 4G coupled with varying tiers of 3G access (3GB, 5GB and 10GB). Starting in November, those same limits will now apply to the total data used, regardless of whether it’s 3G or 4G.

As for hotspot users, the monthly data cap will be set at 5GB of data, again regardless of 3G or 4G.

Going over these limit kicks on the overage meter at $.05/MB.

In its announcement of the change, Sprint reiterates that this does not impact smartphone plans with unlimited data access: “[I]f your phone plan contains unlimited data, you will continue to enjoy unlimited data usage on your phone while on the Sprint network.”

Mobile Broadband Plan and Mobile Hotspot Add-on Changes starting November 2011 [Sprint]