Parts Japan Can't Post: Airbags, Fuel Tanks & Gas Shocks (2026)

You won it. A JZX100 wheel with the hub still on it, a pair of used coilovers off a broken S14, a clean tank for the spare shell. You paste the links into your proxy account and get back one line: we cannot ship this item. No reason, no alternative, no appeal.

The forums will blame customs, or the airline, or the proxy. It is none of those. Japan Post publishes a searchable database — 航空危険物等品名検索, the air dangerous-goods (危険物, kikenbutsu) name search — that grades individual products by name, with the reason and, where one exists, the exact condition that gets you past. Every mark, rule and price below was read off the official pages on 22 August 2026.

Three symbols decide everything

Each entry carries three lines — domestic mail, domestic air carriage, international mail — and each line gets one of three marks. ○ accepted, ✕ refused, and △ refused in principle but acceptable if a stated condition is met. That middle mark is where most drift parts live, which is why “we can’t ship this” is so often the wrong answer rather than the only one. Here is the international column, because that is your column.

Oil is the other half of this and has its own guide: an engine is refused by name, while a gearbox or diff is blocked by residual lubricant and a weight ceiling rather than a ban, covered in the drivetrain shipping guide.

Why it is refused, and why sea mail is no loophole

Japan Post’s English page is blunt. Items covered by the IATA Dangerous Goods Regulations “cannot be sent via international mail, regardless of the types of mail items or means of transportation,” and then: “Please note that the items cannot be accepted even as sea mail.” The Japanese page says the same — 船便扱いでも引受不可.

The rule sits above the post office. Japan’s transport ministry states that to keep aircraft operating safely, carrying dangerous goods as cargo or bringing them aboard is prohibited under Article 86 of the Civil Aeronautics Act. IATA then sorts them into nine classes, and four of those catch a drift parts order: Class 1 explosives (airbag, pretensioner, the flare in the boot), Class 2 gases (dampers, struts, extinguishers, aerosols), Class 3 flammable liquids (anything that has held fuel), and Class 9, where lithium batteries sit. Containers do not dodge it either — sea transport has its own equivalent rulebook, the IMDG Code.

Note what is not caught, because assumptions cost people auctions: brake fluid, antifreeze, radiators and oil filters are all ○ on every line.

Lithium is a destination problem

Japan Post carries lithium batteries only when they are installed in or built into the equipment — a battery on its own, or packed alongside the device, is refused — and only to countries on its published list. That list splits by service. Airmail, SAL and EMS cover the USA, Canada and Australia. The United Kingdom appears only in the surface-mail column. Germany, Italy and Spain appear in neither. A battery-backed logger that posts happily to Sydney has no postal route to Munich.

One useful exception is written into the same document: button-type lithium cells installed in equipment are not classed as dangerous goods by air, and Japan Post names backup-memory data storage as a typical use. That is the coin cell in an ECU. A lithium pack in a data logger is a different animal.

What moving a blocked part actually looks like

Two price tiers, honestly

Where a line genuinely depends on the job, the honest answer is not a percentage. It is actual cost plus a handling fee, quoted as one total before you commit, so the number you agree to is the number you pay.

The one step you cannot do from abroad

Every route above narrows to the same act: somebody standing in Japan has to make the part safe, and then say so, in the right words, on the label.

You cannot unbolt an airbag module from ten thousand kilometres away. You cannot post the live module to a disposal company either, because it is ✕ for ordinary domestic mail too — it has to be handed over in person. And you cannot tell from a photograph whether a used damper is gas-charged; Japan Post is not asking for a guess, it is asking the sender to confirm it and write it in the item-name field. Buyee’s list is a wall of finished nouns — fireworks, ammunition, aerosol spray cans, fire extinguishers, engines — and it never tells you which of your parts becomes acceptable after ten minutes of work, because it does not do the work.

The short version

“We can’t ship this” is usually a database entry, not a judgement — and a lot of those entries are △, which means there is a condition and somebody has to meet it. An airbag module and a bare gas damper have no postal route in any direction. A steering wheel, a seat belt, a suspension assembly and a tyre all do, once the live part is gone and the label says so. A used tank, carburettor or exhaust does not, because “used” is the disqualifying word.

None of that is exotic. It is a spanner, a drain pan, a disposal run and a sentence typed into the right field — all of it in a warehouse in Japan while you are asleep. For choosing a channel before you get this far, the proxy and exporter comparison covers the fees side.