What is the cheapest month to fly to London from the US?

September is the cheapest month, with average round-trip fares around $504. January and February are close behind at 30-40% below summer peak pricing. If you can handle London's winter weather, you'll find the lowest fares between January and March.

How far in advance should I book flights to London?

Book about 6-8 weeks (40-60 days) before departure for the best fares. For summer travel, push that to 3-4 months ahead since demand is higher and prices climb steeply in the final weeks. Booking too early often means missing out on discount fares airlines release closer to departure.

Which London airport is the cheapest to fly into?

Gatwick and Stansted typically offer the cheapest fares, especially from budget carriers like Norse Atlantic. Southend is technically the cheapest at around $92 average, but has very limited routes. Always search all London airports on Google Flights to compare prices for your specific dates.

What is the cheapest airline to fly to London from the US?

Norse Atlantic Airways consistently offers the lowest base fares, starting around $150-$200 one-way from East Coast cities. However, you'll pay extra for bags and meals. Icelandair through Reykjavik and PLAY Airlines are also competitive, especially when you factor in their frequent sales.

What day of the week is cheapest to fly to London?

Wednesday departures are consistently the cheapest, with average fares around $628. Morning flights tend to be slightly less expensive than evening departures. Friday and Sunday are the most expensive days to fly. Shifting your departure by one or two days can save $50-$150.

How to Find Cheap Flights to London

The Quick Answer

You can fly from the US to London for $300-$500 round trip by booking 6-8 weeks ahead, flying midweek, traveling in January-March or September-November, and checking all six London airports. Budget carriers like Norse Atlantic regularly offer one-way fares under $200 from East Coast cities.

Use the Right Search Tools

London is one of the most competitive transatlantic routes in the world. Six airports and dozens of airlines fighting for your business means deals pop up constantly. But you won't find them checking just one site.

Google Flights should be your first stop. Use the calendar view to spot the cheapest departure dates, then set up price tracking so Google emails you when fares drop. The "Explore" map feature is gold for finding cheap dates you hadn't considered.
Skyscanner catches budget carriers that Google sometimes misses. Use the "Whole month" view to compare pricing across an entire month at a glance.
Momondo pulls in fares from online travel agencies and consolidators that other engines overlook. It's worth checking as a final step before booking.
Going.com (formerly Scott's Cheap Flights) sends deal alerts for mistake fares and flash sales. Members have snagged round trips to London for under $300 from cities like Boston, New York, and Miami.

Pro tip: search on these tools, but book directly on the airline's website. You'll have an easier time making changes or getting a refund if your plans shift.

Check All Six London Airports

London has more airports than any other city on Earth. This is your biggest advantage when hunting for cheap flights.

Heathrow (LHR): The biggest and busiest. Legacy carriers dominate, so fares tend to be higher. But competition keeps prices honest on popular routes from New York, LA, and Chicago.
Gatwick (LGW): Norse Atlantic and other budget-friendly carriers fly here. Often $50-$150 cheaper than Heathrow on the same dates. The Gatwick Express gets you to central London in 30 minutes.
Stansted (STN): Ryanair's London hub. Great for connecting cheaply to the rest of Europe after your trip. Farther from central London (about 50 minutes by train) but the savings can be substantial.
Luton (LTN): Another budget carrier hub. Wizz Air and easyJet operate from here. About 30-40 minutes to central London by train.
London City (LCY): Closest to central London (just 8 miles) but serves mostly European routes. Occasionally has good connecting fares.
Southend (SEN): The smallest and cheapest to fly into, with average fares around $92. Limited routes but worth checking if the schedule works.

When searching on Google Flights, type "London" as your destination and it'll search all airports simultaneously. The price difference between airports on the same dates can be $100-$300.

Budget Airlines That Fly to London

The transatlantic budget carrier revolution has made London one of the cheapest European cities to reach from the US.

Norse Atlantic Airways: The standout option. Flies Boeing 787 Dreamliners from New York, Los Angeles, Fort Lauderdale, and Orlando to London Gatwick. Economy Light fares start around $150-$200 one-way. You'll pay extra for bags ($35-$60 per checked bag), meals, and seat selection, but even loaded up it beats legacy carrier pricing.
Icelandair: Not technically a budget airline but regularly offers round trips under $400 through Reykjavik. Their free stopover program lets you spend up to 7 nights in Iceland at no additional flight cost. The connection adds about 2 hours but the savings and bonus destination are hard to beat.
PLAY Airlines: Another Iceland-connecting option from East Coast cities. Base fares from $150-$250 one-way. Everything beyond your personal item costs extra.
Virgin Atlantic: Runs frequent sales from US cities. Not budget per se, but their sale fares compete with budget carriers and you get bags and meals included.

Always calculate the total cost with bags. A $150 Norse Atlantic fare with a checked bag and carry-on runs about $250-$280. That's still great, but it's not $150.

When to Book

Timing your purchase is just as important as choosing the right airline.

The Booking Sweet Spot

For London flights, the ideal booking window is about 6-8 weeks (40-60 days) before departure. Book too early and you're paying the "planning ahead" premium before airlines release discounts. Book too late and you're paying the desperation premium.

For summer travel (June-August), push that out to 3-4 months ahead. Summer London flights sell out fast and prices climb steeply in the last month before departure.

Cheapest Months to Fly

September: The single cheapest month, averaging around $504 round trip. Weather is still pleasant and the summer crowds have thinned out.
January-February: Deep winter means deep discounts. Expect fares 30-40% below summer peak. London's cold and gray, but it's London. There's plenty to do indoors.
October-November: Shoulder season with falling prices and crisp autumn weather. Great for theater, museums, and pub culture.
June-August: Peak pricing. You'll pay 40-60% more than off-season. If you must fly in summer, midweek departures save $50-$100.

Best Days to Depart

Wednesday is consistently the cheapest day to fly from the US to London, with fares averaging around $628. Morning departures tend to be slightly cheaper than evening flights, with prices starting around $608. Friday and Sunday departures are the most expensive.

Departure City Matters

Not all US cities are created equal when it comes to London fares.

Cheapest US Departure Cities

New York (JFK/EWR): The most competitive route. Multiple carriers, multiple daily flights, constant fare wars. Round trips regularly dip to $350-$450.
Boston (BOS): Strong competition from Norse Atlantic, British Airways, and Icelandair keeps fares low.
Miami (MIA): Growing number of options including Norse Atlantic.
Los Angeles (LAX): Norse Atlantic's West Coast option. Fares are higher than East Coast ($500-$700 typical) but sales hit $400-$500 round trip.
Baltimore/Washington (BWI): Often overlooked but Icelandair's presence via Reykjavik makes this surprisingly affordable.

If you're stuck in a city with expensive London fares, consider a positioning flight. A $60 domestic flight to New York plus a $350 transatlantic fare beats an $800 direct flight from your home city.

Connecting Flight Strategy

Direct flights are convenient. Connecting flights are cheaper. That's the eternal trade-off.

Through Reykjavik: Icelandair and PLAY route you through Iceland. Adds 2-3 hours but saves $150-$300. Plus you can do a free stopover in Iceland.
Through Dublin: Aer Lingus offers competitive fares with US preclearance in Dublin, meaning you've cleared customs before you even land.
Through European hubs: Connecting through Amsterdam (KLM), Paris (Air France), or Frankfurt (Lufthansa) can save $100-$200 over direct flights.

One connection adding 2-3 hours is usually worth the savings on a weeklong trip. Two connections or a 6+ hour layover? Probably not.

Mistake Fares and Flash Sales

The absolute cheapest London flights are mistake fares. Airlines occasionally publish fares at a fraction of the intended price due to system errors or currency glitches. Round trips to London have shown up for under $200.

These deals last hours, not days. To catch them:

Sign up for Going.com deal alerts
Follow Secret Flying on social media
Set up Google Flights price tracking on your preferred routes
Check Airfarewatchdog and The Points Guy for fare sale coverage

When you see a mistake fare, book immediately with a credit card. Don't call the airline. Don't wait. Most mistake fares are honored, but they disappear within hours.

Use Points and Miles

Credit card points can eliminate the cost of London flights entirely. A single sign-up bonus (typically 50,000-80,000 points) can cover a round-trip economy ticket.

Chase Sapphire: Transfer points to British Airways, United, or Virgin Atlantic
Amex Membership Rewards: Transfer to British Airways, Delta, or ANA
Capital One: Transfer to British Airways or Turkish Airlines

British Airways Avios are particularly useful for London flights. Off-peak economy awards from the East Coast can be booked for as few as 26,000 Avios round trip. That's an incredible deal when cash fares are $500+.