Korean holidays and plant shutdowns that move your delivery date

A Korean supplier confirms eight weeks. You plan your installation around it, and the shipment arrives eleven weeks later. Nothing went wrong in the shop. The quotation was prepared in a week that contained no holidays, and the manufacturing window happened to cross two periods when the country largely stops.

Two long holidays that move every year

Korea has two major traditional holidays, Seollal and Chuseok, both set by the lunar calendar. Their position in the Gregorian year shifts, so a date that is a working week one year is a shutdown the next.

Each is formally a few days, but the practical effect is longer. Travel volumes are extraordinary, many manufacturers extend the break, and the weeks either side run at reduced output as people take surrounding leave. Subcontractors — heat treatment, plating, machining, testing — take the same days, so a shop that is technically open still cannot complete a sequence that depends on them.

For planning purposes, treat each of these as a period considerably longer than the official holiday, and check the dates for the specific year rather than assuming they repeat.

The fixed dates matter less, with exceptions

The single-day public holidays interrupt less. Where they matter is when one falls adjacent to a weekend and a bridge day is taken, or when several cluster in the same month.

Two periods deserve a note. Early May contains several holidays in close succession, and the summer period sees many manufacturers take a company-wide break of roughly a week. The summer shutdown is not a public holiday and therefore does not appear on any calendar you might look up — it is decided by each company, and the only way to know is to ask. Asking once and recording the answer against the supplier is enough, since the timing tends to be consistent from year to year even though the exact dates are not published.

The end of the calendar year is also worth checking, less for holidays than for the accounting cycle, which affects shipment timing more than production.

Why the quotation rarely says any of this

Lead times are usually built from process times — so many days for material, so many for machining, so many for assembly and test. Those figures are working-day estimates held by production, and they are correct. What converts them into a calendar date is a separate step, and in a busy sales office it is often done by counting weeks forward.

There is no concealment in this. The person quoting has the process times in front of them and the holiday calendar in their head, and the two only come together if someone asks for a date rather than a duration. Domestic customers share the same calendar and make the adjustment automatically, which is why the question rarely arises until a foreign buyer asks it.

This is also why the answer improves so much when you ask for calendar dates. You are not challenging the estimate; you are asking for the conversion to be done explicitly.

Turnarounds set the dates on the other side

If you are buying for a Korean plant rather than from one, the constraint inverts. Process plants schedule turnarounds — planned shutdowns for inspection and replacement — and work that requires the unit to be down can only happen inside that window.

These are planned far ahead and are not moved for a late delivery. A part that misses the window waits for the next one, which may be a year away. This is why buyers on such projects appear inflexible about dates that look arbitrary from outside: the date is not a preference, it is the only time the work can be done.

It also explains a pattern in enquiries. A cluster of urgent requests with short response times usually means a turnaround is approaching and a scope item was added late.

What actually stops during a long holiday

Not everything pauses equally, and knowing the differences lets you plan around them.

The congestion either side is the part most often missed. Shipments are pushed to leave before the holiday and pile up afterwards, so a container booked for the week after a long break competes with everything that was deferred.

Payment timing interacts with this as well. Where production starts against receipt of a down payment, a transfer initiated just before a long holiday may not be credited until afterwards, and the shop will not release material against a payment it cannot see. A few days of banking delay at the wrong point in the calendar can cost two weeks of schedule, which is a disproportionate outcome for something entirely avoidable by initiating the transfer a week earlier.

How to ask so the answer is usable

"When can you deliver?" produces a number of weeks. That number is only as good as the calendar assumptions behind it, which are invisible to you.

Better questions produce checkable answers. Ask for the ex-works date as a calendar date, not a lead time. Ask whether the schedule includes the holiday period falling inside it. Ask when the company's summer shutdown is planned. And ask which subcontracted operations are in the route, since those carry their own calendars.

These are ordinary planning questions, and a supplier who has thought about the schedule answers them easily. A supplier who cannot has not built a schedule — which is itself useful to know at quotation stage.

Inspection dates need the same treatment

Where your order includes witnessed inspection, the holiday calendar affects two parties rather than one.

An inspection scheduled close to a long holiday tends to slip, because the manufacturing step that precedes it slipped. If your inspector is travelling internationally, you are committing to flights against a date that has a known tendency to move.

Two mitigations work in practice. Agree a minimum notice period for inspection calls so late movement is contained, and agree in advance what happens if the inspector cannot attend — whether manufacturing continues against a documented record, or waits. Without that second point, a missed inspection date stops the shop entirely while correspondence crosses time zones at exactly the moment nobody is at their desk.

Padding the date is not the fix

The instinctive response is to add buffer to every Korean delivery date. It feels prudent and it makes things worse in a specific way.

Padding hides where the time is actually going. If you quote your own customer eleven weeks because Korean deliveries "always run late", you lose business on lead time in the cases where eight was real. And when a genuine delay occurs, you have no visibility into whether it is the holiday, a subcontractor, or a problem the supplier has not mentioned.

The alternative costs one email: ask for the schedule as calendar dates with the holiday periods marked. You then know which weeks are working weeks and which are not, and you can commit to your own customer with a date you can defend. Where the schedule genuinely crosses a shutdown, you can decide whether to bring the order forward, split the shipment, or accept the date — all of which are better outcomes than a uniform buffer that is wrong in both directions.

If you send us the item and the date you need it on site, we can look at which weeks in that window are working weeks — the certificate requirements are worth settling at the same time, since they sit on the same critical path. Talk to us about sourcing.