Flights Get Cheaper by the Day You Fly, Not the Day You Book

The deadline still standing on Japanese domestic fares28 days outANA, AIRDO and Skymark have no day-count deadline at all

Picking the weekday you book moves the price about 4%. The weekday you fly moves it 28% on domestic routes in Japan. The staircase of advance fares starting 75 days out was folded away in May 2026, leaving a deadline only at JAL, Solaseed Air and StarFlyer.

The carriers that dropped the deadline now move the price with the seats instead. JAL states on its domestic fare page that the amount varies with the timing of the booking and the number of passengers, according to the predicted remaining seats on each flight. Skymark describes its Imatoku fare the same way: a discount fare whose amount varies with the predicted number of empty seats on each flight. The basis for a low price has moved off the calendar and onto the seat map.

Only useful if you can move your dates

You can shift the departure date by a day or two
You will not change the dates after booking (none of the deadline fares allow a change)
Departure is at least 28 days away
You have not settled on a carrier yet (the deadlines differ by carrier)
Your trip does not straddle New Year or the Obon week

Five out of five and the figures below apply to you as they stand. If any line is off, read only the row for the carrier you will fly in the table further down. The second line is the heavy one: JAL’s Special Saver, Solaseed Air’s Early Sora Value and StarFlyer’s Sorabi all forbid changes to the booking. Chasing a deadline before the dates are settled gives back what you saved the first time you have to redo it.

The fifth line is there because the weekday argument stops working at New Year. On Air Macau’s Tokyo Narita to Macau route, departures on 26 and 27 December were 80,000 yen one way. The median on the same route is 35,800 yen, so no choice of weekday gets you there.

From fixing the date to making the booking

StepWhat to do

STEP 1Settle the weekday firstThe spread across departure weekdays is 28% on domestic routes and 9% on international ones. The dearest is Saturday domestically and Sunday internationally. If the dates have any give, start by ruling those two out.

STEP 2Count back 28 days from the flightPut the boundary date on the calendar. On JAL, Solaseed Air and StarFlyer, one tier of fares drops off your list once that day passes.

STEP 3Check the fare names at your carrierThe same idea carries different names and different cut-offs. Skymark’s Imatoku runs to 3 days out, AIRDO’s DO Value to the day before. On Hokkaido and Kyushu routes the choice of carrier is often made for you, so the route tends to decide this first.

STEP 4Open the same flight twice, days apartWith a fare that moves on remaining seats, one search tells you nothing about whether the number is high or low. Leave two days, open the same flight, and if the figure has risen the inventory has thinned. The reason to wait for a drop disappears right there.

An airport split-flap departure board listing airline names, flight numbers and destinations — Two flights to the same place can price quite differently. With seat-driven fares, the comparison that matters is not another airline but the flight before and after yours on the same route. Photo: Kentagon / CC BY-SA 4.0 (Wikimedia Commons)

Step 4 is there because waiting for a price to fall has very little behind it. Expedia’s figures put the cheapest domestic booking window at 46 to 60 days before departure, an average of about 4,100 yen better than booking 180 days or more ahead, which is the dearest band. Internationally the window is 31 to 45 days and the gap is about 32,800 yen. The international gap is nearly eight times the domestic one because the fares themselves are on a different scale. Either way, “I locked it in six months ago” sits on the expensive side.

The only day-count deadline left is 28 days

CarrierFare with a deadlineDeadlineFare sold until the day before

ANANone—Standard / Simple

JALSpecial Saver28 daysSaver

SkymarkNone—Tasutoku (Imatoku: 3 days)

AIRDONone—DO Value

Solaseed AirEarly Sora Value28 daysSora Value

StarFlyerSorabi28 daysSTAR

This table took its present shape only a few months ago. ANA rebuilt its domestic fares into Flex, Standard and Simple for travel from 19 May 2026. Solaseed Air used the same 19 May as its boundary and folded eight tiers — Bargain 75, Bargain 60, Bargain 35, Bargain 28, Bargain 14 and Tokuuri 7, 3 and 1 — into two, Early Sora Value and Sora Value. Walking down a staircase from the top ended that day.

Apart from the fare table, Solaseed Air also runs limited-time sales. In Solaseed Air’s “Solaseed Special”, on sale from 25 to 30 September 2026, Naha to Ishigaki and Fukuoka was set at 5,390 yen one way and up.

The fares that depend on your age are the ones that still carry a day count. Skymark’s BonvoYoung (U25) is for passengers aged 12 to 25 and runs until 45 days before the flight. The general fares at the same airline have no deadline, while the one aimed at young travellers does — an odd way round. For a trip whose dates settle early, such as a student going home for the holidays, this is the deepest discount on the board.

The average does not turn up on your route

Out of Narita, all seven weekdays came to the same figure

Grouping Air Macau’s price calendar for Tokyo Narita to Macau by departure weekday puts the median at 35,800 yen for every day from Monday to Sunday. Out of Kansai the figures spread a little: 25,400 yen on Monday and Thursday, 27,650 on Tuesday, 29,900 on Friday, and 34,500 on Wednesday, Saturday and Sunday. The cheapest days are Monday and Thursday, and Tuesday — the day Expedia names — comes third of seven.

156 departure dates out of Narita and 161 out of Kansai (departures from 22 September 2026 to 20 March 2027, one way, as displayed on 21 September 2026)

A figure averaged over millions of bookings and the actual run of prices on two routes at one airline are bound to differ. But a reader books one route at a time. I would rather open the calendar for the route I am flying and compare a fortnight of dates than memorise a ranking of weekdays.

The booking weekday moves 4%, and the seats go while you wait

Expedia’s published figures name Friday as the cheapest day to book an international flight and Thursday for a domestic one. The gap against Sunday, the dearest booking day, is an average of 4% in both cases. On a 30,000 yen ticket that is about 1,200 yen.

Waiting until Thursday to collect that 4% pushes a seat-driven fare the other way. Rebooking on Thursday a seat you found on Wednesday only works if the same figure is still there, and nothing guarantees it. Waiting for a weekday was worth something when fares were fixed.

International tickets carry 3,000 yen per departure on top

The International Tourist Tax rose to 3,000 yen per departure from Japan for departures on or after 1 July 2026. Before that it was 1,000 yen. The Japan Tourism Agency leaflet notes a transitional measure: tickets issued on or before 30 June 2026 still attract the earlier rate of 1,000 yen.

Airlines collect this tax as a rule by adding it to the ticket price. Compare one-way fares on their own and you miss 6,000 yen across a return trip. Infants under two are exempt, so multiplying by the number of people in the family will not reconcile. For cutting the costs that sit outside the fare itself, the savings ranked by how much they move has more levers in it.

What happens once 28 days have passed

Passing the deadline does not empty the aircraft. JAL keeps Saver, Solaseed Air keeps Sora Value and StarFlyer keeps STAR on sale until the day before. ANA’s Standard and Simple and AIRDO’s DO Value run to the day before as well. Skymark is the one exception: Imatoku stops 3 days out and Tasutoku carries the rest of the way to the day before. In practice “too late” does not arrive until the evening before the flight.

There are prices that only appear at the last minute. On the same Air Macau calendar, the lowest figure of the whole period, 3,000 yen one way, sat on departures between 23 September and 2 October — the ten days beginning the day after the calendar was read. A stretch where ten days out beats two months out does exist, and it runs straight into the idea that earlier is always cheaper.

Last-minute prices lean heavily on the route and the season, though. They are something a traveller with movable dates picks up, not something to aim at. If you are waiting on a fare that appears at irregular intervals, reading the next round off the previous ones is steadier — the record of past Jetstar sale rounds lays out how many come each year and when. To set the cash price against redeeming miles, the break-even on a 7,000-mile round trip has the arithmetic.

If the destination is still open, you can also pick the flight first and build the trip around it. Shaping the dates around a cheap one-way weekday changes how you move once you land. That way of building an itinerary is written up in the Fuji Five Lakes route done entirely by bus.

Common questions: is last minute cheaper, can it be changed, what about children

Is it cheaper to buy at the last minute?

It depends on the route and the season. Expedia’s averages put the cheapest window at 46 to 60 days out domestically and 31 to 45 days internationally, with the last minute on the rising side. Yet on Air Macau’s calendar a stretch of departures within ten days all sat at 3,000 yen one way. Treat the average and the single route in front of you as two separate things.

Can I change the dates after buying a 28-day fare?

You cannot. JAL’s Special Saver, Solaseed Air’s Early Sora Value and StarFlyer’s Sorabi are all sold on terms that forbid a change to the booking. If the dates might still move, the fare sold until the day before works out cheaper in the end.

Does the same thinking apply to children’s tickets?

Domestic discount fares have separate child settings, and the deadline works differently from one fare to the next. On the International Tourist Tax, infants under two are exempt. Multiplying a single figure by the number of travellers will not match the total, so check the breakdown on the booking screen.

SOURCES