It is advisable to secure your boarding stubs, ticket copy and baggage tags. You may be required to produce a copy of your passport as well.
If your baggage has been declared missing despite our efforts to locate your baggage - a copy of your passport, passenger ticket receipt, baggage tag receipt from the missing bag, boarding pass stub, and receipts/proof of purchase for the items claimed in the form will be required to support the claim and enable us to process the same.
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For other enquiries contact your local offices, contact details can be found in the following link https://www.qatarairways.com/en/worldwide-offices.html