A Section 321 shipment is a U.S. shipment type for goods clearing through U.S. Customs and Border Protection. This entry type allows for the release of shipments valued at $800 or less at the border.

To qualify for Section 321 release, a shipment must not exceed $800 in value and cannot be part of multiple lots covered by a single order or contract where the total value would exceed $800. Additionally, CBP may deny Section 321 release based on risk considerations that may differ among various types of merchandise.

As of March 7, 2016, the limit for Section 321 informal entries increased from $200 to $800.

On November 26, 2018, U.S. Customs and Border Protection began a phased approach to address non-compliance for Section 321 on ACE Manifests. Starting January 1, 2019, CBP requires an ACE Manifest for all Section 321 shipments. Failure to include these shipments on ACE Manifests may result in a monetary penalty starting at $5,000 for the first offense.

Shipments released under Section 321 are exempt from duty and tax.