Every international package must clear US Customs and Border Protection (CBP). For the vast majority of consumer orders under $800, that process is fully automated and takes 1-3 days at an ISC facility. No forms, no fees, no action required. It's only the outliers that get held.
This guide explains exactly what happens to your package at US customs, how long it typically takes, and what you can do if it gets stuck.
Track your international package's customs status in real time on ParcelsZen. We show ISC arrival, customs clearance, and post-clearance USPS delivery all in one view.
How US Customs Works
US Customs and Border Protection is a federal law enforcement agency under the Department of Homeland Security. Its job is to regulate and process international trade, collect import duties, and enforce US trade laws.
When your international package arrives at a US port of entry (usually by air at major international airports), CBP screens all incoming packages. The vast majority of consumer packages are cleared automatically through the Automated Broker Interface (ABI) without being physically opened or examined.
The De Minimis Threshold: $800
The most important rule for US consumers importing goods is the de minimis threshold: packages with a declared value under $800 USD can enter the USA duty-free and with minimal customs formalities.
This applies to the vast majority of consumer packages from AliExpress, eBay international sellers, SHEIN, Temu, and similar sources. Most individual orders from Chinese marketplaces are well under $800, which is why they clear customs quickly and without duty charges.
Under $800 declared value = duty-free entry into the USA. This is the de minimis threshold and it covers the vast majority of consumer online orders from international sellers.
The International Service Centers (ISCs)
Air mail packages typically pass through one of the USPS International Service Centers (ISCs) in:
- New York (JFK)
- Chicago (O'Hare)
- Los Angeles (LAX)
- Miami
- San Francisco
Your tracking will show 'Arrived at ISC [city]' followed by 'Processing Complete' and then forwarded for domestic delivery. The ISC process typically takes 1-3 days for standard packages.
What Triggers a Customs Hold?
Most packages sail through customs, but some are flagged for inspection. Common triggers include:
- Packages from countries with high rates of counterfeit goods
- Items that are restricted or require special licensing (firearms, certain pharmaceuticals, agricultural products)
- Under-declared values — sellers who mark a $200 item as worth $5 on the customs form may trigger scrutiny
- Random inspection — CBP randomly selects packages for inspection regardless of contents
- High-value shipments over $800 that require formal entry and duty assessment
Track Your Package Through Customs
See exactly where your international package is — including ISC status and customs clearance updates.
Track Your PackageHow Long Does Customs Hold a Package?
- Normal package: 1-3 days at the ISC for scanning and automated clearance
- Package selected for inspection: 3-7 additional days
- Package requiring duty assessment: 5-10 additional days — you may receive a notification
- Package with a serious issue (prohibited items, etc.): Indefinite hold — CBP may contact you directly
Duties and Taxes: What You Might Owe
- For packages under $800: No duties, no action required
- For packages $800-$2,500: CBP may assess duties under an informal entry process. The carrier (FedEx, DHL, UPS) typically handles this and bills you separately.
- For packages over $2,500: A formal customs entry is required, which usually involves a customs broker. You'll receive a CBP Form 4646 or the carrier will contact you with payment instructions before release.
Most customs holds are routine random inspections or automated reviews. The majority resolve within 3-7 days without any action required from you. Only act if you receive a specific notification from CBP or your carrier.
What to Do If Your Package Is Stuck in Customs
If your tracking shows 'Arrived at ISC' or a customs-related status for more than 7 days, here's what to do:
- Check for notifications from CBP or your carrier requesting documentation. If you owe duties, the package won't move until you pay.
- Contact the carrier — USPS at 1-800-275-8777, FedEx, DHL, or UPS at their respective numbers — with your tracking number and ask for a status update.
- For packages stuck at the ISC for 10+ days, you or the sender can open a formal inquiry with USPS or CBP.
Frequently Asked Questions
Track Your Package Through US Customs on ParcelsZen
Track your customs status on ParcelsZen from ISC arrival through post-clearance USPS delivery. Most packages clear silently — 'Processing Complete' appears without any action on your part. It's only after 7 days at the ISC that calls and escalation actually move things.
- Arrived at ISC: In US customs — normal 1-3 days
- Processing Complete: Customs cleared — domestic delivery begins
- Stuck 7+ days? Check for duty notifications, contact carrier
- Stuck 10+ days? Open formal inquiry with USPS or CBP
- Under $800: No duties — fastest automatic clearance