Starting on Wednesday, the Dallas-based carrier will charge customers $35 for their first checked bag and $45 for their second checked bag. The bag fee change will also apply to existing flight itineraries changed on or after May 28, Southwest confirmed to "Good Morning America."

It’s the last day to book a flight on Southwest Airlines without being hit with a fee to check bags after the airline abandoned a decades-long luggage policy that executives once described as key to differentiating the budget carrier from its rivals.

Southwest Airlines has put a price tag on checking bags, a coveted free perk that is about to disappear as part of substantial changes the carrier is making to its service.