A "10kg check-in bag" in 2026 usually refers to a specific, lower-cost baggage tier offered by budget airlines like Ryanair, EasyJet, or Aer Lingus. Unlike a standard 23kg suitcase, this is a small suitcase (often the same size as a carry-on) that you must drop off at the check-in counter to be stored in the aircraft hold. This tier was created in 2026 to help passengers who have liquids or items that aren't allowed in the cabin but don't need a full-sized trunk. It is critical to note that if your bag weighs 10.1kg or more, these airlines will often charge a heavy "excess weight" fee at the counter. In 2026, some airlines also offer a "10kg Carry-on" option, which allows you to bring that same bag into the cabin. Always double-check your digital boarding pass; "Check-in" means you leave it at the desk, while "Carry-on" means you keep it with you.