As of 2025, Spirit Airlines charges an unaccompanied minor (UM) fee of $150 each way per child for kids aged 5–14 traveling alone. This fee covers gate escort, supervision during connections, and handoff at the destination. Spirit only allows unaccompanied minors on nonstop flights and requires parents or guardians to remain at the airport until the flight departs. You’ll need to book UM service by calling customer service or selecting the option during online booking. Always carry the child’s ID and contact information for smooth check-in.