For a U.S. sender, an international package can be delayed, returned, or charged additional import costs even after a carrier accepts it. Customs paperwork, destination restrictions, carrier terms, and the agreement about who pays import charges all affect the result.

Before paying for postage, verify three things: the destination allows the item, the declaration is accurate, and the sender and recipient understand who may pay duties, taxes, brokerage, or other fees. These checks apply to gifts, personal belongings, online returns, and occasional sales.

What controls an international shipment?

Several separate systems may apply:

• Destination customs and government agencies decide whether the contents may enter, how they are classified, and what duties or taxes apply.
• The carrier or postal service sets packaging, size, weight, dangerous-goods, tracking, delivery, and claims requirements.
• The merchant's return policy controls whether you receive a refund or a return label. It doesn't override customs rules or carrier terms.
• Your shipping agreement may assign responsibility for postage, brokerage, duties, taxes, and handling charges. Customs may still assess the shipment independently.

A carrier accepting a parcel means it accepted the parcel for transport. It doesn't mean destination customs has cleared it.

Common international shipping mistakes U.S. senders should avoid

1. Using a vague or inaccurate description

Customs needs a description that identifies the contents, not just a label for the transaction. "Merchandise," "gift," "parts," or "clothes" may not provide enough information. A return should not be described as a gift, and a gift still needs an accurate contents declaration.

Record:

• What the item is
• Its material or main components
• The quantity
• Whether it is new, used, or a return
• Its truthful value
• The country where it was made, when the form requests it

For example, "two used cotton T-shirts, personal clothing" is more useful than "clothes." Keep a photo or copy of the declaration before handing over the parcel.

2. Guessing the HS code

The Harmonized System uses a common six-digit foundation. Individual countries may add more digits to classify products in greater detail. A classification difference can affect duty, permits, and restrictions.

Don't choose a code simply because it produces the lowest charge. Check the destination country's tariff information, or ask the carrier's customs team or a qualified broker if the product is difficult to classify.

3. Declaring an artificially low value

The declared value should be truthful and supported by a receipt, order record, or other evidence. Marking an item as worth $1 when it is not can lead to revaluation, delay, penalties, or a claim dispute.

A low-value package isn't automatically duty-free. CBP guidance generally describes informal entries as personal packages or commercial items valued below $2,000. An informal entry is an entry category, not a blanket exemption from duties, taxes, inspections, or documentation.

4. Ignoring destination restrictions

A product that can be mailed within the United States may be restricted or prohibited in another country. Food, plants, seeds, meat, medicines, cosmetics, alcohol, animal products, and used equipment often receive special treatment.

Check both lists before paying for postage:

1. The destination country's customs or import rules
2. The carrier's prohibited and restricted-items list

For items sent back to the United States, CBP says packages containing fruits, vegetables, meat, or other agricultural products may be inspected to verify that they meet U.S. requirements. A small quantity or personal-use label doesn't necessarily remove those requirements.

If a permit, certificate, or approval is required, obtain it before shipping. A carrier may transport a parcel that destination customs later refuses.

5. Treating batteries and hazardous materials like ordinary goods

Lithium batteries, dry ice, aerosols, perfumes, chemicals, and some medical or laboratory materials can trigger dangerous-goods rules. Hiding the contents or removing a warning label can put handlers and passengers at risk and may cause the package to be refused.

For USPS shipments, Publication 52 says each mailable lithium battery must meet the UN Manual of Tests and Criteria, Part III, 38.3 testing standard. It also generally requires mailpieces containing lithium batteries to use rigid outer packaging, subject to stated exceptions.

Before shipping:

• Identify whether the battery is installed in equipment, packed with it, or shipped by itself.
• Check the carrier's current dangerous-goods instructions.
• Confirm that the destination accepts the item.
• Use the required markings, packaging, and documentation.
• Ask the carrier's dangerous-goods team if you're uncertain.

Those are USPS requirements. Private carriers and destination countries may impose additional rules.

6. Sending documents with conflicting information

A customs declaration, commercial invoice, receipt, shipping label, and import permit should tell the same story. Mismatched descriptions, values, weights, sender names, or recipient details can delay clearance.

Depending on the service, the shipment may require a postal customs declaration or a commercial invoice. Prepare the documents before the parcel is collected and check:

• Sender and recipient names and addresses
• Telephone number or email, if requested
• Detailed contents
• Quantity and value
• Country of origin, when required
• HS code, where required
• Shipping terms and the party responsible for import charges
• Any permit or certificate

A customs-clearance guide from UPS Supply Chain Solutions describes clearance as the process of officially passing through a country's customs authority and highlights the transaction information used to assess duties and taxes. A shipping label alone doesn't replace that information.

7. Assuming the postage price includes every import charge

The amount shown for postage may cover transportation only. Depending on the service and destination, the sender or recipient may also face duties, taxes, brokerage, disbursement fees, remote-area charges, storage, or other handling costs.

Before shipping or ordering an international return, ask:

• Are duties and taxes paid by the sender or recipient?
• Is brokerage included?
• Could the carrier collect payment before delivery?
• Who pays if customs holds or returns the package?
• If this is a return, does the merchant provide instructions for recovering any eligible import charges?

For freight shipments, get free-time and daily storage, demurrage, or detention terms in writing where applicable. Those charges depend on the carrier, port, equipment, and contract, so a generic per-container estimate can't predict the bill for a particular shipment.

8. Leaving responsibility for charges unclear

A shipping agreement may say that the sender or recipient is expected to pay, but an informal assumption is not enough. Write down who is responsible for transportation, duties, taxes, brokerage, disbursement, storage, and return costs.

Tell the recipient how import charges will be collected and what may happen if payment or documents are not provided. If a merchant arranged a return, keep its instructions and ask what the label actually covers.

9. Choosing the cheapest service without checking what it includes

A low postage price may come with slower delivery, limited tracking, fewer delivery attempts, no signature, restricted claims, or little customs support. Compare the complete service:

• Delivery estimate and route
• Door-to-door or post-office delivery
• Tracking quality
• Signature and proof of delivery
• Customs-brokerage process
• Coverage and claim limits
• Return handling
• Size, weight, fuel, and remote-area surcharges

For a valuable or irreplaceable item, check the carrier's liability and insurance exclusions before shipping. Coverage terms may limit a claim involving prohibited contents, an inaccurate declaration, or inadequate packaging.

10. Packing for the first mile instead of the whole journey

International parcels may be sorted, loaded, unloaded, inspected, and transferred between postal systems. A "fragile" sticker doesn't replace internal protection.

Use a strong outer box, fill empty space, protect corners, seal all openings, and remove old labels or barcodes. Measure and weigh the parcel after it is fully packed. Carriers use different volumetric-weight formulas, so use the formula shown for the selected service rather than relying on a universal calculation.

11. Failing to keep evidence of the shipment

If a parcel is lost or damaged, you may need to show what you sent, how it was packed, and what it was worth. Before sealing the package, photograph:

• The item and serial number, if applicable
• Internal padding
• The closed parcel
• The shipping label
• The receipt and tracking number

Keep those records until delivery and until any carrier claim deadline has passed. Save the purchase record or other proof of value as well.

12. Treating a customs hold as a status message you can ignore

A tracking message such as "held in customs" doesn't necessarily mean the item has been seized. It may indicate a document request, duty assessment, inspection, address problem, or restriction review.

Use the carrier's website or official phone number to find out:

1. Which party currently has the package
2. The exact reason for the hold
3. What document or payment is needed
4. The deadline for responding
5. Whether storage charges are accumulating

Don't rely on a text message or email link to explain the status. Start with the official tracking record and contact channel.

13. Missing a deadline or submitting a false correction

Once a shipment is held, waiting can increase costs or lead to a return. Send corrections through the carrier's verified process and provide only accurate documents. Don't submit a false replacement declaration just to release the parcel.

On its page about sending items back to the United States, CBP warns that goods not cleared within 15 days of arrival could incur expensive storage fees. That warning is specific to the guidance on that page; it shouldn't be treated as a universal deadline for every carrier or country. If the carrier or customs notice gives a deadline, ask what is required before it passes.

14. Trusting urgent payment requests or fake shipping messages

A message that demands immediate payment to release a package may be genuine, but it may also be a phishing attempt. Scammers can copy carrier branding, use a real tracking number, or ask you to pay a new bank account.

Protect yourself by:

• Typing the carrier's website address yourself instead of clicking the message link
• Comparing the tracking number with your receipt or order
• Calling the carrier using contact details from its official website
• Confirming any change to bank details through an independent channel
• Avoiding unverified wire transfers, gift cards, or cryptocurrency payments
• Saving emails, invoices, payment records, and message headers

If you paid a suspected scammer, contact your bank or payment provider promptly and ask what recovery or fraud-reporting options are available. The FTC's contact guidance directs people targeted by illegal business practices or scams to its fraud-reporting process.

15. Assuming a merchant return label solves the customs problem

A merchant may provide a return label or promise a refund, but its return policy doesn't override the destination's customs rules or the carrier's terms. The label may cover transportation without answering who pays duties, taxes, brokerage, storage, or return charges.

Before dispatching an international return, ask the merchant for written instructions about:

• The required contents description and declared value
• Any return authorization or invoice
• The party responsible for import-related charges
• What happens if customs holds or returns the parcel
• The conditions for receiving a refund

Keep the merchant's instructions with your shipping records.

A pre-shipment checklist

Before you hand over an international package, confirm:

• [ ] The destination allows the item.
• [ ] The carrier allows the item on the selected service.
• [ ] The description is specific and truthful.
• [ ] The value is supported by a receipt or other record.
• [ ] The country of origin is correct when the form requires it.
• [ ] The HS code is checked when required.
• [ ] The customs form, invoice, and label agree.
• [ ] Batteries, liquids, and other regulated contents meet the carrier's rules.
• [ ] The packed dimensions and weight are accurate.
• [ ] You know who is responsible for duties, taxes, brokerage, and handling.
• [ ] Any merchant return instructions are complete.
• [ ] Tracking, signature, and coverage limits suit the item.
• [ ] You have photographed the contents and saved the receipt.
• [ ] The recipient knows how import charges will be collected.

What to do if the package is held, returned, or seized

Start with the official tracking record, not a text message or an email link. Ask the carrier or postal service for the precise status and the agency or department handling the issue.

Gather the tracking number, declaration, invoice or receipt, proof of payment, photographs, and any permit. Submit only the documents requested, and keep copies of everything.

If the contents are prohibited, ask whether the available options are return, abandonment, export, or disposal. The carrier may not be able to override a customs decision. If the package is returned, confirm whether a new declaration or additional postage is required before sending it again.

For a U.S.-bound mail entry, CBP guidance says a duty protest may involve sending a letter and the yellow copy of CBP Form 3419Alt to the CBP office identified on the form. The same guidance lists refusing delivery as another way to protest duty. Follow the current instructions on the form and CBP's page. This isn't a general promise that duties or shipping charges will be refunded.

Shortcuts that don't solve the problem

Changing a commercial purchase to a gift, declaring an unrealistically low value, or using a vague description doesn't make the contents acceptable. Reshipping the same restricted item with a different carrier doesn't remove the destination rule. An unverified "customs release" invoice may be a scam, and insurance bought after a parcel is lost or damaged can't restore the required evidence. Keep the receipt until delivery and any claim deadline has passed.

Frequently asked questions

Does marking a package as a gift avoid customs charges?

Not automatically. A gift must still be declared accurately, and any exemption depends on the destination's rules, value limits, contents, and required documentation.

Are packages under $2,000 duty-free in the United States?

No blanket rule follows from the informal-entry threshold. CBP generally describes informal entries, but entry classification, duty, tax, inspection, and documentation are separate questions.

Who pays international customs fees?

The answer depends on the shipping agreement, merchant terms, carrier process, and destination rules. Confirm the payer before dispatch and ask whether a return label covers only transportation or also import-related charges.

What should I do when tracking says "held in customs"?

Contact the carrier or broker through an official channel, ask for the exact reason and response deadline, then provide accurate documents or payment through the verified process. Don't wait if storage charges may apply.

Can a carrier release a prohibited package?

Usually, the carrier can't override the destination authority's decision. Ask whether the parcel can be returned or what formal process applies, and don't alter the declaration to make the item appear acceptable.