Aero K 50% Off to Cheongju With Code GOTOCJJ: Seven Routes From Japan Until 20 September

Discount on the fare50%Seven Japanese cities to Cheongju / round trips only, taxes and fuel surcharge excluded

Airline

Aero K

Routes

Narita, Ibaraki, Nagoya, Osaka, Fukuoka, Kitakyushu and Okinawa to Cheongju

Sale period

2026-08-13 – 2026-09-20

Travel period

2026-09-01 – 2026-09-30 (23 to 28 September excluded)

Deadline

2026-09-20 in Korea Standard Time, or the first 5,000 bookings, whichever comes first

Checked on

2026-09-14

Aero K is handing out a promotion code, GOTOCJJ, that takes 50% off the fare on round trips out of Japan to Cheongju. It runs from 13 August to 20 September 2026, covers seven routes, and stops at the first 5,000 bookings.

Six excluded days leave 24 to fly, and the first of them lands on the last day of Japan’s five-day weekend

Two clocks run at once here. The code dies on 20 September; the flights run to 30 September. Selling closes ten days before travel does, which rules out deciding on a late-September trip in late September. Within those 30 days, 23 to 28 September are excluded, so 24 days are actually flyable — and where those six fall is the whole story. In 2026 Monday the 21st is Respect for the Aged Day and Wednesday the 23rd is the Autumnal Equinox, which turns Tuesday the 22nd into a citizens’ holiday and makes Saturday the 19th to Wednesday the 23rd a five-day break.

The exclusion opens exactly where the holiday closes. A round trip that takes the whole break and flies home on the 23rd cannot be built on this code, and because round-trip purchase is a condition, a return leg inside the excluded window drags the outbound leg out of scope with it. Using the break means coming home by the 22nd or moving into the first half of the month. Buy on 20 September, the last day of selling, and the choice of travel dates comes down to four: the 21st, 22nd, 29th and 30th.

The 50% is narrower than it looks as well. The terms state that the discount applies to the air fare only and that fuel surcharges, airport taxes and other charges are excluded. Japan–Korea is a short hop where the fare line is small and the taxes are not, and since 1 July 2026 departures from Japan also carry the international tourist tax of JPY 3,000. The smaller the fare, the less halving it removes, so the effective saving on the total lands well under 50% — and a carrier quoting “one way from X, taxes included” is not comparable without doing that arithmetic first. Fare displays in general are unpicked in LCC cheap flight booking techniques.

Put those two conditions together — fare-only discount, round trip compulsory — and one tactic follows: pick the expensive days for both legs. Halving a peak-day fare removes more money than finding a cheap day and halving that, which inverts the usual advice. Avoid the excluded window and build around September weekends and the arithmetic works in your favour. The special fare also carries 15 kg of checked baggage, which matters because Basic Lite normally charges for it separately; 15 kg is enough for a short trip to Korea unless shopping is the point of the trip, in which case it can be gone on the way out. Cheongju is not Seoul either, so what a night in Seoul costs belongs in the total alongside the rail or bus transfer from Cheongju.

When does the next airfare sale come? Six weeks of records and what is bookable now →

Source: Aero K official event page, “50% off flights to Korea, September departures only” (sale period, travel period, excluded window, the seven routes, promotion terms, Basic Lite round-trip condition, 15 kg baggage), checked 2026-09-14; the English interface carries the same event at /en-US/event-benefit/event/394, checked 2026-09-20 / Japanese public holiday dates from the 2026 calendar / Photo: 4300streetcar, CC BY 4.0 (Wikimedia Commons), Aero K Airbus A320 HL8562