New U.S. Section 301 Tariffs on ASEAN Imports: Key Implications for Exporters and Importers

U.S. trade policy affecting ASEAN has changed materially in 2026. The Administration terminated the IEEPA-based additional ad valorem duties in February, including the former reciprocal-tariff measures; Section 232 and Section 301 duties were expressly unaffected. A separate 10% temporary import surcharge imposed under Section 122 took effect on February 24 for 150 days and expired on July 24, 2026, absent congressional extension.¹²

Section 301: new ASEAN country-level duties

USTR’s July 23 final action in its forced-labor import-policy investigations is now the principal new country-level tariff measure affecting ASEAN. For covered merchandise entered on or after July 24, 2026, Cambodia, Indonesia and Malaysia are subject to an additional 10% Section 301 duty. The Philippines, Singapore, Thailand and Vietnam are subject to an additional 12.5% duty. Brunei Darussalam, Lao PDR, Myanmar and Timor-Leste were not among the economies covered by the action.³

The action applies broadly to products of the covered economies, subject to exemptions identified by USTR. USTR also directed the establishment, when feasible, of tariff-rate quotas for certain textile and apparel imports from Cambodia, Indonesia and Malaysia based on the use of U.S. inputs.⁴

Section 232 and customs enforcement

Separate Section 232 measures remain significant. The current metals regime imposes 50% duties on covered aluminum, steel and copper products, 25% on certain derivative products, and a temporarily reduced 15% rate on specified fixed industrial machinery and power equipment. Certain advanced computing chips and derivative products are subject to a 25% Section 232 tariff, with specified U.S. end-use exceptions.⁵⁶

Patented pharmaceuticals and associated ingredients are subject to a separate Section 232 regime. The general rate is 100%, with lower rates or zero treatment available in specified circumstances, including approved onshoring and pricing arrangements. Generic pharmaceuticals are not presently subject to the Section 232 pharmaceutical tariff. The proclamation provides a July 31, 2026 effective date for listed companies and September 29, 2026 for other companies.⁷

The former $800 duty-free de minimis exemption remains suspended for commercial shipments regardless of country of origin. CBP’s new postal informal-entry process became effective July 24, 2026. In addition, a June 3 Executive Order directs tighter importer-of-record, bonding, disclosure, vetting and audit requirements and prioritizes enforcement involving forced labor, misclassification, undervaluation and illegal transshipment.⁸⁹

Additional proceedings to watch

USTR is separately investigating structural excess capacity and production in manufacturing sectors, including Cambodia, Indonesia, Malaysia, Singapore, Thailand and Vietnam; no tariff action has yet resulted from that investigation. USTR also initiated a Vietnam-specific Section 301 investigation concerning intellectual-property protection and enforcement on May 29; that proceeding likewise has not yet produced additional tariffs.¹⁰¹¹

ASEAN country-level Section 301 snapshot

The rates above are additional country-level Section 301 duties, not all-in U.S. tariff rates. Ordinary HTSUS duties, Section 232 measures, antidumping/countervailing duties and other charges must be assessed at the product and transaction level.

For ASEAN exporters and U.S. importers, landed-duty exposure should be reviewed by HTSUS classification, country of origin and applicable trade-remedy measure. Origin, valuation and supply-chain documentation should be reviewed alongside the tariff calculation.

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1. Executive Order 14389, Ending Certain Tariff Actions (Feb. 20, 2026), expressly ending specified IEEPA additional ad valorem duties while leaving Section 232 and Section 301 duties unaffected. ↩︎
2. Proclamation 11012, Imposing a Temporary Import Surcharge to Address Fundamental International Payments Problems (Feb. 20, 2026), 91 Fed. Reg. 9339 (Feb. 25, 2026) (10% surcharge effective Feb. 24 through 12:01 a.m. EDT July 24, 2026 unless extended by Congress). ↩︎
3. Office of the U.S. Trade Representative, Notice of Actions in Section 301 Investigations Related to the Failure to Impose and Effectively Enforce a Prohibition on the Importation of Goods Produced With Forced Labor, 91 Fed. Reg. 47318 (July 28, 2026); USTR, USTR Takes Action in Forced Labor Section 301 Investigations (July 23, 2026). ↩︎
4. 91 Fed. Reg. 47318 (July 28, 2026) (product exemptions and direction to establish, when feasible, textile and apparel TRQs for Bangladesh, Cambodia, Indonesia and Malaysia based on U.S. inputs). ↩︎
5. Proclamation 11002, Adjusting Imports of Semiconductors, Semiconductor Manufacturing Equipment, and Their Derivative Products Into the United States (Jan. 14, 2026), effective Jan. 15, 2026. ↩︎
6. Proclamation 11032, Further Adjusting the Tariff Regimes for Imports of Aluminum, Steel, and Copper Into the United States (June 1, 2026). ↩︎
7. Proclamation, Adjusting Imports of Pharmaceuticals and Pharmaceutical Ingredients Into the United States (Apr. 2, 2026), clauses 3-5 (100% general rate for covered patented products; specified 20%, 15%, 10% and zero-rate treatment; generics excluded at this time; phased effective dates). ↩︎
8. Executive Order 14411, Strengthening Customs Enforcement (June 3, 2026), including importer-of-record, bonding, disclosure, vetting and audit directives and enforcement priorities for forced labor, misclassification, undervaluation and illegal transshipment. ↩︎
9. U.S. Customs and Border Protection, Indefinite Suspension of the De Minimis Exemption for Mail Shipments and New Postal Informal Entry Process, 91 Fed. Reg. (June 24, 2026), effective July 24, 2026 except as specified. ↩︎
10. USTR, USTR Announces Section 301 Investigation of Vietnam’s Acts, Policies, and Practices Related to Intellectual Property Protection and Enforcement (May 29, 2026). ↩︎
11. USTR, USTR Initiates Section 301 Investigations Relating to Structural Excess Capacity and Production in Manufacturing Sectors (Mar. 11, 2026) (including Singapore, Indonesia, Malaysia, Cambodia, Thailand and Vietnam). ↩︎

Key Contacts

David Doran

David Doran

Founding Partner, Head of Trade & Tariffs

Founding Partner, Head of Trade & Tariffs

Thailand

Melissa Welebir Kuhn

Melissa Welebir Kuhn

Of Counsel

Of Counsel