Frontier carry-on size is restricted to 10 x 16 x 24 inches, including bag handles, wheels, and straps. If carry-on bags exceed this limit, you may have to check them at the boarding gate, which comes with an additional charge.

In 2026, Frontier Airlines is notoriously "picky" and strict about carry-on and personal item dimensions to maximize ancillary revenue. Every gate at Frontier's hubs is equipped with a metal bag sizer, and agents frequently require passengers to demonstrate that their bag fits completely—including wheels and handles—without being forced. A "Personal Item" must be no larger than 14"H x 18"W x 8"D; if it exceeds this by even an inch, you will likely be charged an "at-the-gate" fee that can be $100 or more. For "Carry-On" bags (24"H x 16"W x 10"D), which you must pay extra for, the weight limit is strictly capped at 35 lbs. In 2026, Frontier's boarding software often flags passengers who haven't pre-purchased a bag, prompting agents to check every single item. To survive a Frontier flight, it is essential to measure your bag at home and avoid "over-stuffing," as a bulging bag that doesn't slide easily into the sizer will trigger an immediate fine.