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."

Southwest Airlines has updated its checked bag policy, and passengers will start paying extra tomorrow. Southwest has long allowed passengers to bring a guaranteed free checked bag, but that is changing tomorrow as the airline adopts a new policy.