When should you book flights?
- Book 1 to 3 months ahead for domestic flights and for international flights, book 3 to 6 months if it’s during a busy travel period like summer or the holidays.
- Don’t stress about the booking day, but fly midweek if you can.
- Use price alerts to keep tabs without losing your sanity.
- Avoid last-minute bookings unless you have nerves of steel.
- Be flexible with dates, times, and even destinations if you want to score real bargains.
Why it works
Most airlines use dynamic pricing, which means ticket prices bounce around based on demand, booking trends, and how close you’re getting to the travel date.
Prices usually start low, climb steadily, then spike in the last 2–3 weeks before departure. That last-minute price hike? It’s real.
Set Skyscanner price alerts to get notified every time the price drops or rises. Other good ones are Google Flights, Hopper, and Kayak.
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My Portugal vacation price-tracking experience
Starting in February, I began monitoring flights to Lisbon for my family of four. Every few days, I’d check Skyscanner and log the prices in my spreadsheet.
The fluctuations were wild – some days the price would jump by 75% for total price, only to drop back down a week later. This experience taught me that booking flights to get a good ‘deal’ is a bit of luck and understanding patterns and timing.
So, after all the searching, spreadsheeting, and second-guessing, here’s what I’ve learned about the best time to book flights for domestic or international.
For domestic flights, don’t wait too long
If you’re booking flights within the same country, two to three months ahead is your sweet spot.
Most experts say booking one to three months before departure is the sweet spot. Book too close to the date, and prices tend to spike.
In fact, according to Google Flights, the cheapest fares are usually found 21 to 60 days before departure, with 44 days being the magic average.
And according to Expedia’s 2025 Air Travel Hacks Report, travellers saved up to 24% by booking domestic flights at least 28 days in advance compared to booking last-minute.
So if you’re planning a short getaway, maybe a weekend in Belfast, set your price alerts and book somewhere in that window.
For weekend trips or school holidays, you’ll want to stretch that booking window even further—ideally three months out.
For international flights, plan ahead
When you’re crossing borders—especially long-haul—it’s a different game. Flights to Europe, Asia, or Africa are usually cheapest when booked three to six months in advance.
For our Lisbon trip, we booked two months ahead. That felt like the right balance: not too early to overpay, and not too late to panic.
Best days to fly (not book)
Flying out on Wednesday or Saturday tends to be cheaper for both domestic and international trips. That’s because fewer people fly midweek, and airlines usually drop prices to fill those seats.
Weekends are popular—and airlines know it. So they often charge more for Friday, Sunday, and Monday flights.
According to Expedia’s 2025 report, domestic flights on Saturdays are about 17% cheaper than on Sundays. For international trips, Wednesdays and Saturdays tend to be the best-value days to fly (source: Hopper).
Early mornings and late nights are underrated
If you’re trying to cut costs, flying early in the morning or late at night can make a real difference.
Kayak shared data with Condé Nast Traveller UK, showing that early or late flights are typically cheaper and they’re less crowded too. They are less in demand and therefore cheaper.
If you’re travelling with kids like I was, this can be a bit tricky. But if you’re travelling solo or as a couple, it’s worth considering.
Forget the “Tuesday Myth”— use price alerts and flexible dates
I used to believe Tuesday afternoons were the golden window for cheap tickets. But turns out, there’s no magical booking day.
What works better? Setting up price alerts on Skyscanner, Google Flights, or Hopper. That’s how I caught the dip for our Lisbon flights. Also, try searching with “anywhere” or “flexible dates” if you don’t have a fixed plan. Sometimes adjusting by just one day can save you a chunk of money.
Eventually, when the numbers hit the lower end of my spreadsheet, I locked it in.
FAQ
- Use the “Everywhere” Search Feature: If your dates are flexible, try Skyscanner’s “everywhere” feature or Kayak’s “Explore” map. It’s a fun way to see where your budget can take you.
- Go Incognito or Clear Cookies: Some sites may bump prices based on your search history. Try browsing in private mode if you’re checking the same route repeatedly.
- Be Flexible With Dates: Even shifting your travel by one day can make a big difference in price. When you see a good deal, don’t wait too long—it might not last.
We flew from the UK to Lisbon from 25–29 May 2025. I started tracking prices in February using Skyscanner, manually recording daily fares into Excel. I noticed fares were fairly stable until mid-April, then started creeping up. Booking around four weeks out turned out to be the best move.
We chose an evening flight to avoid peak-hour chaos and to save money, and I must say—it worked. The airport was less crowded, the kids were calmer (well, somewhat), and the fares were cheaper compared to morning or midday flights.
Final thoughts
If there’s one thing I’ve learned, it’s this: there’s no single perfect time or day to book flights.
But tracking early, staying flexible, and using tools like price alerts can make a huge difference, especially if you’re booking for a whole family.
If you’ve got a trip coming up, start watching prices now. Don’t wait until the last minute, and don’t trust every “hack” you hear.
Keep it simple, track consistently, and let the data guide you. That’s what helped me get us to Lisbon without blowing the budget—and I’d do it the same way again.
