Here’s KAYAK’s latest data on when to book flights and the cheapest days to fly, looking at one-way and round-trip tickets. While there’s no single best day to book flights, when you book and the days you fly can have quite an impact.
In this article
Best day to book flights
When to fly domestically?
When to travel internationally?
When to travel in Europe?
Tools to help you find the best time to book
Best time to book FAQs
Is there a cheapest day to book flights?
Although there is no specific cheapest day to book, there are some data-backed trends to help you get cheaper flights. Rather than focus on the day, focus on the timing:
| Trip type | Best time to book |
|---|---|
| Within the UK | 30 days before departure |
| Within Europe | 30–36 days before departure |
| Long-haul international | 14–30 days before departure |
Overall, according to KAYAK search data, booking flights around a month in advance seems to be the sweet spot.
What about during busy travel periods?
Popular travel periods tend to mean higher fares. Book flights early, when you can, for:
- Summer holidays (June-August)
- Easter holidays
- Christmas through New Year’s
- Bank holiday weekends (May bank holiday weekends etc.)
What are the cheapest days to fly within the UK?
- Cheapest day to fly out: Wednesday (~£70)
- Cheapest day to return: Wednesday (~£58)
In general, flying midweek around the UK is the cheapest option. Unsurprisingly, the weekend (Friday – Sunday) is the most expensive time to fly. Sunday was the most expensive day for returns, with average ticket prices of around £93.
What are the cheapest days to fly within Europe?
- Cheapest day to fly out: Tuesday (~£133)
- Cheapest day to return: Wednesday (~£109)
For flights within Europe, KAYAK data recommends flying out on Tuesday and returning on Wednesday. If a one-night trip seems hasty, Thursday is the next cheapest option.
Much like travel in the UK, or long-haul, weekend travel is consistently the most expensive.
What are the cheapest days to fly internationally?
- Cheapest day to fly out: Wednesday (~£605)
- Cheapest day to return: Wednesday (~£539)
Long-haul international flights shared some similarities with domestic flights. There is a midweek dip in prices, while the weekend is the most expensive time to fly. Friday–Saturday departure specifically.
In theory, this means you are most likely to get the lowest price for a week-long international return flight if you fly Wednesday-to-Wednesday. For oneway flights, Tuesday is the chepeast – but only just.
What else should I know about the best time to fly?
Airfares fluctuate for all kinds of reasons, and KAYAK’s data is merely a reflection of overall trends. That said, no matter when you fly, KAYAK can help you fin the best deals. As an award winning metsearch engine, KAYAK does the work for you.
So even if your travel plans don’t always allow you to book on days with the lowest airfares, KAYAK can help you find an airfare that’s affordable for you, whether you’re looking to explore the UK or see the rest of the world.
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KAYAK tools to help you find the cheapest time to book and fly.
KAYAK offers a variety of Flight Filters to customise your search, including a price filter to keep your budget in line. That’s not enough to determine the cheapest time to buy flights, though, so there are plenty more free tools to help you get there.
- KAYAK Price Alerts: Set alerts for specific routes and receive email notifications when prices drop. Run a flight search and try it now.
- KAYAK Price Forecast: Find this tool when you run a flight search on KAYAK. Price Forecast analyses historical data to predict whether prices on your route are likely to rise or fall, helping you decide whether to book now or wait.
- Flexible date search: Use KAYAK’s flight search calendar to compare prices ±3 days from your selected travel dates, full weekends, or entire months. Green indicates cheaper.
- KAYAK Explore: See where you can fly for the lowest fares from your home airport using KAYAK Explore.
For best results, set any alerts 2-4 months before your intended travel dates. When you see a price that meets your budget, book it – waiting for a lower fare that may never come can backfire.
FAQ
Every airline’s goal is to get the most money possible for each seat sold, which means airfare pricing is one of the purest examples of supply and demand in action. To do this, popular leisure routes and cabins (economy) are priced highly further in advance, which is when holiday travellers tend to book.
These seats tend to go down over time as the airline seeks to fill the plane before take-off. Business routes and cabins (business/first) are priced lower upfront to fill minimum quotas, then increased over time, as short-notice corporate travellers scramble to get a remaining seat.
This is more common in economy class cabins and on leisure travel routes (i.e., holiday destinations). For business-class and first-class seats, the reverse is more often true: prices increase as the departure date approaches.
These seats tend to go down over time as the airline seeks to fill the plane before take-off. Business routes and cabins (business/first) are priced lower upfront to fill minimum quotas, then increase over time as short-notice corporate travellers scramble to secure a remaining seat.
Flight prices may change frequently. As flights fill or don’t, airlines will continuously adjust prices to maximise profits, so fares can change multiple times throughout the day. Flight prices vary depending on the season, too, the seats you want to book, and the balance between supply and demand of seats.
Sometimes. Airfare prices change regularly based on supply and demand and the airline’s resulting prediction of how it can maximise income on remaining seats. Computer software is often responsible for analysing this and updating fares. This can certainly happen at night, but it is equally likely to happen any time of day, any day of the week.
Average flight prices of economy class per day of the week and for each 7 – 183 search days ahead of departure in 2026 for round-trips broken down by departures and returns aggregated for domestic and international routes, respectively. KAYAK analyzed search data conducted on kayak.co.uk between 01/01/2025 – 18/03/2026 for traveling anytime until 30/06/2026
The post The best time to book flights & the cheapest day to fly. appeared first on KAYAK Blog UK.
