To collect lost luggage, the process begins immediately at the airport's Baggage Service Office (often located near the carousels) where you must file a Property Irregularity Report (PIR). You will be given a 10-character file reference number (e.g., LHRBA12345) which is essential for tracking. In 2026, most major airlines also allow you to track and manage this claim via their mobile app. Once your luggage is located, you typically do not have to return to the airport to "collect" it. The airline is legally obligated (under the Montreal Convention) to courier the bag to your home or hotel at their expense. The delivery driver will usually contact you to coordinate a drop-off time. If you choose to pick it up yourself to save time, you must return to the airport's arrivals level with your PIR receipt and a government-issued photo ID. If your bag is declared officially "lost" after 21 days, the "collection" process shifts to a financial one, where you submit an itemized list of contents and receipts to the airline's claims department to receive monetary compensation up to approximately $1,700 per passenger.