When a checked bag doesn't show up, go to the airline's baggage desk before leaving the airport. File a missing or delayed-baggage report - often called a Property Irregularity Report (PIR) - and get the case number. Keep your bag-tag receipt and boarding pass. Give the carrier a delivery address that will still work, and start saving receipts for necessary purchases.

Don't treat 21 days as a waiting period. On an international itinerary covered by the Montreal Convention, a written complaint about delayed baggage generally must reach the airline within 21 days after the bag is made available to you. If the bag still hasn't arrived 21 days after it should have arrived, it may generally be treated as lost for purposes of enforcing treaty rights. Neither rule excuses a late report.

Tracing the bag and seeking reimbursement are related but separate tasks. The report helps the airline locate and deliver it. Receipts, an inventory, and proof of value support a claim for expenses or lost contents.

Delayed, damaged, or lost: name the problem

The airline may call the case delayed, missing, or lost while its tracing process is underway. Ask which status it has assigned, which form covers expenses, and which form covers a permanently lost bag. For a U.S. flight, the carrier's contract of carriage and applicable federal rules matter more than a generic checklist.

Ten lost-baggage mistakes that make a claim harder

1. Leaving old baggage tags on the suitcase

Previous destination stickers and claim tags can make a suitcase harder to identify. Remove them before each trip, including small barcode labels from earlier flights.

Use a current external tag with your name, mobile number, email address, and destination lodging. Put the same information inside the bag in case the outside tag comes off. A quick photo of the suitcase and its current tag at check-in can also help establish what the bag looked like.

Passports, cash, keys, irreplaceable medication, and other essentials belong in your carry-on, not in checked baggage.

2. Searching too long instead of reporting the bag

A quick check of nearby carousels, the oversized-baggage area, and a transfer belt is reasonable. Ask an airport employee whether bags from the flight were moved. If the suitcase still isn't there, stop searching and report it before the baggage desk closes.

Leaving with no report can make the timeline harder to prove. If the desk is busy, wait for the report process rather than relying on a verbal promise that someone will call.

3. Leaving the airport without a case number

At the baggage desk, provide the bag-tag number, flight details, routing, suitcase description, and a delivery address where you can actually receive the bag.

Before leaving, save or photograph:

• The PIR or delayed-baggage report
• The case or tracing number
• The baggage-tag receipt
• The airline's baggage contact details
• Any instructions for claiming emergency expenses

If no desk is open, use the airline's online reporting system as soon as possible and save the confirmation screen. A phone conversation without a case number is difficult to document later.

4. Assuming the PIR is the compensation claim

A tracing report usually gives the airline the information it needs to search for the bag. It may not also ask for reimbursement of clothing, toiletries, transportation, or other costs.

Ask the agent or check the airline's baggage website:

1. Which form covers emergency expenses for delayed baggage?
2. Which form covers the contents of a permanently lost bag?
3. What documents and deadlines apply?
4. How should you update the claim if the bag arrives?

If there is a separate expense form, send it while the search continues. You can add later receipts or revise the request rather than trying to reconstruct every purchase weeks afterward.

5. Letting 21 days become a waiting period

Use 21 days as a deadline to track, not as a reason to postpone action. Report the bag on the day it goes missing and keep receipts from the first day.

For an international Montreal Convention claim, the 21-day mark can affect both the treatment of an undelivered bag as lost and the deadline for a written delayed-baggage complaint after delivery. Once the bag is delivered, send that written complaint within the applicable period even if you already reported the delay at the airport.

U.S. domestic flights don't have one universal 21-day baggage-claim rule. Check the carrier's contract and claim instructions.

6. Failing to document what was in the bag

Memory becomes less reliable as time passes. Write an inventory as soon as you can, including:

• Item descriptions and approximate purchase dates
• Brand, model, size, color, and serial number when relevant
• Purchase receipts or order confirmations
• Photos taken before the trip
• The approximate replacement cost

Be accurate. Inflated estimates, duplicate entries, and claims for items excluded by the airline's contract can weaken the file. For an unusual or valuable item, proof of ownership and value is stronger than a round-number estimate.

7. Buying necessities without keeping receipts

Airlines may reimburse reasonable and necessary expenses caused by a baggage delay, but eligible items and spending limits depend on the carrier, route, and applicable law. There is no universal daily clothing allowance for every U.S. traveler.

Buy practical replacements rather than an upgraded vacation wardrobe. Keep itemized receipts and note the date and reason for each purchase. A credit-card statement may show the merchant and total without showing what you bought, so retain the detailed receipt whenever possible.

Ask the airline whether it has spending guidance before making nonessential purchases. If the bag is delivered quickly, the carrier may question expenses that appear excessive or unrelated to the delay.

8. Treating an AirTag as a replacement for an airline report

An AirTag or another tracker can show that a suitcase is at an airport, on another aircraft, or near a delivery facility. It doesn't replace the PIR, prove the value of the contents, or require the airline to release the bag immediately.

Take screenshots that show the location and time. Add them to the airline's baggage case instead of relying only on social media or a phone call. Don't enter a restricted airport area or confront someone at a private address based on a tracker signal. If the evidence suggests theft, provide it to the airline and local law enforcement.

9. Assuming a connecting bag will always be transferred

At check-in, ask whether the bag is tagged to your final airport. On some international connections, customs rules require passengers to collect bags at the first U.S. airport and recheck them. Separate tickets may also mean the next airline isn't set up to transfer the bag automatically.

Check the destination printed on the tag before boarding. If you must reclaim and recheck the suitcase, follow that instruction even if you expected it to continue to a later airport. Keep every baggage tag from every segment.

10. Accepting a denial or voucher without checking the terms

If the airline denies the claim, ask for the reason and the policy or contract provision behind it in writing. Reply with a short timeline, the PIR, the bag tag, receipts, photographs, and the specific amount requested.

Some carriers have separate service guarantees for bags that miss a short delivery target. Those programs may offer points or a travel credit and usually have their own claim window. They are carrier policies, not a substitute for a baggage report or a universal compensation right. NerdWallet's airline baggage breakdown describes examples, but check the airline's current terms before relying on one.

Before accepting a voucher, check whether it is a goodwill payment or a full settlement of the baggage claim. Don't assume it covers future expenses unless the terms say so.

What a U.S. baggage claim may cover

Different forms of recovery follow different rules. For U.S. travelers, keep these categories separate:

• Checked-bag fee refund: On flights covered by U.S. Department of Transportation rules, the checked-bag fee generally must be refunded when the bag is significantly delayed and the rule's other conditions are met. The threshold is generally 12 hours after gate arrival for a domestic flight, 15 hours for an international flight scheduled to take 12 hours or less, and 30 hours for a longer international flight. The DOT says refunds are due within seven business days when the fee was paid by credit card and within 20 calendar days for other payment methods.
• Emergency expenses: Necessary, reasonable, documented purchases may be claimable under the airline's policy and applicable law. This is separate from a refund of the baggage fee.
• Permanently lost or damaged contents: The airline may require proof of ownership and value. Liability limits and exclusions depend on the route and the carrier's contract.
• Travel insurance or card benefits: A travel policy or card benefit has its own covered causes, waiting periods, limits, deductibles, and documentation rules. It doesn't replace the airline claim.

For many international journeys, the Montreal Convention baggage liability limit is 1,288 Special Drawing Rights per passenger. The dollar equivalent changes with the exchange rate. This is a ceiling, not an automatic payment; you still need to prove the loss and account for applicable exclusions.

For more detail on U.S. rules, see the Department of Transportation's baggage guidance. Don't apply an international treaty limit automatically to a domestic flight.

A practical claim file and follow-up plan

Use one physical or digital folder for the incident. Include:

• Boarding pass, itinerary, and baggage-tag receipt
• PIR or delayed-baggage case number
• Photos of the suitcase, tag, and any damage
• A simple timeline of reports, calls, messages, and delivery updates
• Written communications with the airline
• Tracker screenshots, if available
• Itemized receipts for necessary purchases
• An inventory with proof of value
• The delivery address and dates you supplied
• Copies of every submitted form

Work through the file in this order:

1. Report the missing bag immediately. Get the case number before leaving the airport. If the desk is closed, use the airline's online process and save its confirmation.
2. Confirm delivery instructions. Update the airline if you change hotels, leave the destination, or become unavailable at the address originally supplied.
3. Buy only necessary replacements. Keep detailed receipts and avoid luxury purchases.
4. Submit the expense claim promptly. Use the airline's baggage portal or written process; a PIR alone may not be enough.
5. Inspect a returned bag immediately. Photograph any damage and send written notice within the deadline that applies to the route.
6. Submit a contents claim if the bag is declared lost. Use the airline's form, include the inventory and proof of value, and preserve a copy.
7. Appeal a denial in writing. Ask for the precise policy reason and address each missing document or disputed expense.
8. Escalate if the airline stops responding. You can file a complaint through the DOT complaint process for a U.S.-related air-travel issue. A DOT complaint gives the airline an opportunity to respond, but it isn't a guaranteed award of private compensation.

Notify your travel insurer or card benefits administrator early if you may use that coverage. Tell each provider about the other claim, and don't collect twice for the same expense.

Trains and cruises use different procedures

DOT baggage rules and the Montreal Convention don't automatically govern train or cruise luggage. Report a missing or damaged bag to the operator, station, port, terminal, or ship staff before leaving if possible. Get an incident number, preserve tickets and tags, photograph the damage, and check the operator's claim deadline.

A cruise line may have separate rules for port transfers and embarkation baggage. A train operator may treat unattended or checked baggage differently from an airline. An AirTag can help locate a suitcase, but the operator's ticket contract and travel-insurance policy control the claim.

FAQ

Should I wait 21 days to file a lost-baggage report?

No. Report the bag immediately. On some international claims, 21 days affects when an undelivered bag can be treated as lost or when a written delayed-baggage complaint is due. It isn't a reason to postpone tracing or documenting expenses.

Can an airline refuse to reimburse my replacement clothes?

It can challenge purchases that aren't reasonable, necessary, documented, or allowed under its policy. Keep itemized receipts, buy practical replacements, and ask for the airline's expense instructions before making larger purchases.

Does an AirTag prove that the airline owes me money?

No. A tracker can support the timeline and help locate the bag, but the airline will still need the baggage report and evidence supporting your expense or contents claim.

Is a checked-bag fee refund the same as lost-luggage compensation?

No. A fee refund concerns the price paid to check the bag. Reimbursement for emergency purchases or the value of lost contents is a separate claim with different evidence and limits.

What should I do if the airline rejects my claim?

Request the denial and policy reason in writing. Then appeal with your PIR, bag tag, timeline, photos, inventory, and receipts. If the airline doesn't resolve a U.S.-related complaint, consider filing through the DOT complaint process. Save the submitted appeal and the airline's final response with the rest of your claim file.