The September 2026 Import Deadline Calendar: Six Dates That Cost Money, and What to Do Before Each

The September 2026 Import Deadline Calendar: Six Dates That Cost Money, and What to Do Before Each

September opened with three federal actions in four days — a new Section 232 tariff, a hard ACE reject date, and a proposed rule that would make importers custodians of their suppliers' export paperwork. The rest of the month is a sequence of dates, each of which moves real money for a specific population of importers. This is the working calendar: what fires, when, who it hits, and the move that is still available before it does.

Dates are listed in order. Where FreightFigures has already published a deep dive, it is linked; this page is the index, not the full analysis.

Already in force: Section 232 drone tariffs (September 3)

The Section 232 duties on unmanned aircraft systems took effect at 12:01 a.m. ET on September 3. CBP's September 2 CSMS guidance sets an additional 100% under 9903.08.21 for unmanned aircraft with thermal imaging, docking stations, docking-station parts, and parts or components for a UAS with a maximum take-off weight above 25 kg — and an additional 25% under 9903.08.22 for unmanned aircraft without thermal imaging.

Two things to note if you are still filing drone entries this month. First, the parts expansion is deferred: beginning February 9, 2027, 9903.08.22 also covers parts and components for any UAS except the over-25-kg class already caught by the 100% heading. Second, goods admitted to a foreign trade zone must go in under privileged foreign status unless eligible for domestic status, which means the FTZ does not shelter the rate. Reduced rates apply to products of the United Kingdom, Japan, Liechtenstein, South Korea, Switzerland, Taiwan, and EU member states, and drawback is available where the usual conditions are met.

Full analysis: Section 232 drone tariffs, effective September 3 and the Blue List deadline post-mortem.

Monday, September 8, 12:01 a.m.: Canada's counter-tariffs take effect

Ottawa's response to the Section 338 action becomes operative Monday. The published list runs to 874 tariff lines covering C$27.6 billion in U.S. goods at 15%, 25%, or 50%, with each rate matched to the U.S. rate on the corresponding product. Steel and aluminum move to 50%. Dairy, seafood, appliances, agricultural equipment, pulp and paper, electronics, furniture, and apparel are all on the list.

The one structural feature that matters for freight already moving: Canada's countermeasures do not apply to U.S. goods in transit to Canada on the day they come into force. A load that leaves a U.S. dock bound for Canada before 12:01 a.m. Monday clears at the old rate. That is the mirror image of the Section 338 posture on the U.S. side, which offered no in-transit relief when the 50% duty went live August 19.

If you are on the import side of this — Canadian-origin goods that have been carrying Section 338 since August 19 — nothing changes Monday, but the escalation makes a negotiated rollback less likely in the near term, which lengthens the expected hold time on any bonded Canadian inventory you have been floating. We ran the float / re-export / withdraw math in the Section 338 drawback piece and the retaliation analysis.

Monday, September 14: ACE starts hard-rejecting copper entries without smelt and cast data

This one is a filing failure, not a tariff, and it will stop cargo. Per CBP's August 31 CSMS (#69711865), beginning September 14 ACE will return F794 ADDTNL DEC TYPE RQRD FOR ARTICLE as a fatal error on any entry summary for copper articles under HTSUS 8544.42.10, 8544.42.20, 8544.42.90, or 8544.49.10 that does not carry the required 54-record Type 12 declaration — primary country of smelt and country of cast. Secondary country of smelt remains optional. U.S.-origin goods are exempt.

The reporting requirement itself has been mandatory since July 30; what changes on the 14th is that a missing declaration goes from a warning to a rejected summary. Importers who do not know the smelt or cast country may report "OTH", which clears the validation but is the kind of answer that draws a CF-28 later.

If your supplier cannot produce smelt and cast data by the time the container lands, there is a practical alternative to filing "OTH" and hoping: hold the goods in a bonded warehouse under a warehouse entry, which does not require the Type 12 declaration, and file the consumption withdrawal once the data is in hand. Full breakdown: copper smelt/cast hard reject, September 14.

Tuesday, September 15: the CIT hears the AD/CVD refund motion

Importers whose entries paid IEEPA duties and also carry antidumping or countervailing duties have been the population CAPE cannot reach — those entries cannot liquidate while the AD/CVD proceeding is open, so there is nothing to reliquidate. On September 15 the Court of International Trade hears oral argument on a motion brought for Aditya Birla Chemicals and Pack Perfect asking the court to declare now that all such entries must ultimately be refunded, with the mechanism worked out later.

Nothing changes for that population until the court rules, but the hearing is the first procedural movement it has had. Context, including the Phase 3 delay and the $1.7 billion frozen for missing ACH details: IEEPA refund status, September 2026.

Retroactive to July 1: USTR conforms four Section 301 China exclusions to the new HTS numbers

Buried in the September 2 Federal Register: USTR amended four Section 301 China product exclusions so they track the July 1 statistical (484(f)) HTS updates. The affected numbers are 8413.91.9039, 8413.91.9046, 8413.91.9059, 8413.91.9099, 3926.90.9915, and 3926.90.9920, and the amendment is effective for goods entered or withdrawn from warehouse on or after 12:01 a.m. July 1, 2026.

Why it belongs on a money calendar: if you have been entering goods under one of those subheadings since July 1 and paying Section 301 because the exclusion no longer matched the renumbered line, you now have a refund claim. CBP has said entry guidance is coming; once it lands, the mechanism is a post-summary correction on unliquidated entries or a protest on liquidated ones. Pull the entries now so you are ready to file the day the CSMS issues.

Thursday, October 22: postal informal entry grace period ends; CPSC eFiling reaches the mail

Two rules converge on the same date. The carve-out that has let PGA-regulated, Chapter 98/99, and FTA-claim mail shipments ride the postal informal entry process expires October 22, after which they need formal entry or Entry Type 13 — filed by a licensed broker. Separately, CPSC announced September 1 that eFiling of certificates becomes mandatory for mail shipments under Entry Type 13 beginning October 22, submitted as full or reference message sets through ACE. Mail entries were previously outside CPSC eFiling because CBP collected no entry data on them; Type 13 changed that.

Full rule and the 14-element data set: the mail rule's last grace period.

Tuesday, December 1: comments due on CBP's Heightened Import Disclosures ANPRM

CBP's September 2 advance notice of proposed rulemaking asks whether importers should be required to obtain, retain, and potentially submit the documentation their foreign supplier filed with its own customs authority before export, whether the MID should be replaced with fuller manufacturer/producer/shipper/exporter/seller identification, and whether CTPAT should carry traceability and cybersecurity obligations. It is a proposal, not a rule — but it is the only window in which importers set the terms. Comments are due December 1, 2026. What to say and which questions to answer: the ANPRM, explained.

The dates that are not on this calendar

CAPE Phase 3. CBP told the CIT on August 25 that reliquidation of finally liquidated entries is delayed with no new date. If you were budgeting a Phase 3 refund for September, move it to "unknown."

Section 122. The 10% universal surcharge expired by statute at 12:01 a.m. July 24. Anything still quoting it as a current cost is stale.

Section 232 metals transitional rates. The 15% and 25% temporary headings (9903.82.20–.26 and the Annex I-C structure) run through December 31, 2027, then revert to standard rates. Not a September problem, but if you are signing 2027 supply contracts on metal-intensive equipment, the cliff is inside the contract term.

The one-table version

| Date | What fires | Who it hits | Move before the date | |---|---|---|---| | Sep 3 (done) | Section 232 UAS: 100% / 25% | Drone importers | Confirm 9903.08.21 vs .22; FTZ = privileged foreign | | Sep 8 | Canada counter-tariffs, 15/25/50% | U.S. exporters to Canada | Ship before 12:01 a.m. — in-transit goods exempt | | Sep 14 | ACE F794 fatal error, copper smelt/cast | 8544.42.x / 8544.49.10 filers | Get Type 12 data, or warehouse entry until you have it | | Sep 15 | CIT oral argument, AD/CVD IEEPA refunds | Importers with AD/CVD + IEEPA entries | Nothing to file; watch the ruling | | Retro to Jul 1 | Sec. 301 exclusions renumbered | 8413.91.90xx / 3926.90.99xx | Pull entries; PSC or protest once CBP issues guidance | | Oct 22 | Postal grace ends; CPSC eFiling for Type 13 | Mail-channel importers | Line up a licensed broker; build the eFiling message set | | Dec 1 | ANPRM comments due | Every importer | File a comment on documentation burden and cost |

Stacking it up

Several of these dates touch the same entry. A copper-bearing product from Canada, for example, carries Section 232 metals duty on full customs value, Section 338 at 50% since August 19, and a smelt/cast declaration that becomes fatal on September 14 — all on one line. The tariff stacking calculator runs the layers in the right order, and importers reconciling classification across a renumbered HTS often check the line-level math in software such as Zonos before their broker files. (Disclosure: this is an affiliate link — FreightFigures may earn a commission if you sign up, at no additional cost to you. See our full affiliate disclosure.)

Where bonded storage fits this month

Three of the seven dates above have a bonded-warehouse answer. Copper entries that land before smelt and cast data is confirmed can sit under a warehouse entry rather than file "OTH" or eat an F794 reject. Canadian goods carrying Section 338 can keep floating while the September 8 escalation plays out, with duty owed only on what you withdraw. And any inventory whose Section 301 exclusion status is in flux after the July 1 renumbering can be held and withdrawn once CBP's guidance settles which line applies. If the cargo is coming through the Port of Charleston, the facility is minutes from the terminals — the form below reaches the warehouse directly.

FAQ

When do Canada's counter-tariffs on U.S. goods take effect? 12:01 a.m. on September 8, 2026. Rates are 15%, 25%, or 50%, matched to the U.S. rate on the corresponding product, across 874 tariff lines worth about C$27.6 billion. Goods in transit to Canada on September 8 are exempt.

What happens to copper entries on September 14, 2026? ACE begins rejecting entry summaries for HTSUS 8544.42.10, 8544.42.20, 8544.42.90, and 8544.49.10 that do not report primary country of smelt and country of cast, returning fatal error F794. Importers may report "OTH" if the country is unknown. U.S.-origin goods are exempt.

Can a bonded warehouse entry avoid the copper smelt/cast reject? A warehouse entry does not require the consumption-entry Type 12 declaration, so goods can be held in bond while the importer obtains the smelt and cast data, then withdrawn for consumption with a complete declaration.

What is the September 15 CIT hearing? Oral argument on a motion by Aditya Birla Chemicals and Pack Perfect asking the Court of International Trade to order that all antidumping/countervailing entries that paid IEEPA duties must ultimately be refunded.

Which Section 301 China exclusions were amended on September 2? Four exclusions were conformed to the July 1, 2026 HTS statistical changes, covering 8413.91.9039, 8413.91.9046, 8413.91.9059, 8413.91.9099, 3926.90.9915, and 3926.90.9920, effective retroactively to July 1. CBP will issue entry guidance.

When does CPSC eFiling apply to mail shipments? October 22, 2026, for mail shipments filed under Entry Type 13, using the full or reference message set in ACE.

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