Sourcing poly mailer bags from China
Poly mailer bags from China carry a flat 6% UK duty on ordinary plastic bag lines. Confirm the polymer and construction before choosing the code, and check Plastic Packaging Tax separately from customs duty. Cambridge China Bridge sources poly mailer bags.
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UK duty on polyethylene poly mailer bags
Heading 3923 covers plastic articles for conveying or packing goods and plastic closures. Polyethylene poly mailer bags fall within 3923 21 00 00, covering sacks and bags of polymers of ethylene. The table repeats this code for different polyethylene mailer specifications; printing, return strips and recycled content do not create separate lines in the supplied tariff facts.
Read from the UK Trade Tariff on 4 December 2026, the ordinary duty for polyethylene bags from China is 6%. This line lists no anti-dumping duty, countervailing duty or attached import control. It includes a tariff suspension restricted to a specified multilayer damp-proof bag construction. Do not assume an ordinary waterproof mailing bag qualifies: check the complete suspension wording against its materials and film thicknesses.
Confirm the resin and complete construction before selecting your commodity code, especially for mixed-material or padded products. Check Plastic Packaging Tax separately from customs duty. For the wider heading and an alternative mailer construction, see paper padded mailers.
| Goods | Commodity code | Duty | Anti-dumping or countervailing duty on China |
|---|---|---|---|
| Unprinted polyethylene poly mailer bags | 3923 21 00 00 | 6% | None |
Specify usable size, film and adhesive closure
Specify usable internal width and length separately from the closing flap, plus any gusset, film thickness and tolerances. State the polyethylene grade, permitted recycled content, colour, opacity and surface finish. Identify whether the thickness applies to an individual wall or the flattened bag, so the factory and inspector measure the same thing.
Agree the adhesive strip position, release liner, opening method and any return closure. Approve artwork, print placement and barcode readability on a filled bag. Trial samples with your actual contents, shipping labels and packing process, checking seam strength, puncture resistance and whether the seal lifts after storage.
Packaging must use the minimum weight and volume needed to keep the product safe and hygienic. Obtain bag weights and material records for your packaging assessment. HMRC says plastic packaging components containing 30% or more recycled plastic are not chargeable for Plastic Packaging Tax. Check tax registration separately, and assess whether packaging producer responsibility obligations apply to your business.
Worked duty example
Illustrative example, not a quote: Illustrative order of 4,000 printed polyethylene poly mailer bags under 3923 21 00 00, invoiced at £1,200 free on board, with £312 of freight and insurance to the UK. The customs value is £1,512. Duty at 6% is £90.72. Import VAT at 20% is charged on the customs value plus duty, £1,602.72, so it is £320.54. Import taxes total £411.26; a VAT-registered importer can usually reclaim the VAT, so the lasting cost is the £90.72 of duty. The import duty and VAT guide explains each step.
Inspection checklist
Dimensions and film: measure usable internal space, flap, gusset and film thickness against the approved specification; compare bag weight and opacity with the sample.
Seams and closure: fill bags with the intended contents, stress the side and bottom seams, and check adhesive coverage, liner removal and seal lifting under agreed conditions.
Print and labels: compare artwork, colour and print position with the approved sample; rub the print and check label adhesion and barcode scanning on filled bags.
Packing and records: count bags against carton quantities, check batch identification and contamination, and match material records to the supplied batch. Agree the inspection scope before shipment.
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What goes wrong
The advertised size may include the flap, leaving too little room for the contents. Thin or uneven film can split around corners, while weak seams open when the bag is stretched. A mailer that looks opaque when empty may reveal its contents when filled.
Adhesive can lift from dusty or unsuitable film, and a return strip can be unusable if the opening tears through it. Changes to resin or recycled material can alter feel, opacity and sealing behaviour. Keep an approved filled sample, require agreement before material changes, and inspect arrival stock before using it for customer dispatch.
Cambridge China Bridge sources these products for UK businesses, checking the factory and the documents before shipment. See factory verification. For repeat volumes, see container programmes.
Frequently asked questions
What is the UK import duty on poly mailer bags from China?
Ordinary polyethylene mailers under 3923 21 00 00 carry 6% duty. No anti-dumping or countervailing duty is listed. The specialised damp-proof bag suspension is not a general relief for mailers.
Does the quoted mailer size include the flap?
Ask explicitly. Specify usable internal width and length separately from the flap and gusset, then approve a filled sample with your actual contents.
Do recycled poly mailers avoid Plastic Packaging Tax?
HMRC says components containing 30% or more recycled plastic are not chargeable for the tax. Obtain supporting material records and check registration separately.
How do I check whether the adhesive seal works?
Fill sample bags, apply the seal using your packing process and check for lifting after agreed storage conditions. Test liner removal, seam strength and any return closure.