SEA - BSL

$402 Find Cheap Flights from Seattle to Basel

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from Seattle to Basel departing on 7/22. Fares are subject to change and may not be available on all flights or dates of travel. Click the price to replicate the search for this deal.
1 adult
1 adult, Economy

KAYAK searches hundreds of travel sites at once for deals on flights to Basel EuroAirport Swiss

 
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Seattle to Basel, as well as popular online travel agencies
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Seattle to Basel, as well as popular online travel agencies
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Flights Deals

Cheap Flights from Seattle to Basel (SEA-BSL)

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Seattle to Basel that are departing in the next months. While these flights were available on KAYAK in the last 72 hours, prices and availability are subject to change and deals may expire.
Discover the best prices for you by selecting your travel dates on KAYAK.

Recent round-trip flight deals from Seattle to Basel

Mon, Aug 18 - Tue, Aug 26
Lufthansa Logo
2:20 pm - 1:40 pmSEA-BSL
14h 20m1 stop
Lufthansa Logo
8:30 am - 8:42 pmBSL-SEA
21h 12m2 stops
$513Lufthansa
Find Deal
Tue, Aug 19 - Tue, Aug 26
Lufthansa Logo
7:00 am - 7:35 pmSEA-BSL
27h 35m2 stops
Lufthansa Logo
8:30 am - 8:42 pmBSL-SEA
21h 12m2 stops
$517Lufthansa
Find Deal
Mon, Aug 18 - Tue, Aug 26
Delta Logo
6:40 pm - 1:10 pmSEA-BSL
33h 30m1 stop
Delta Logo
10:10 am - 5:35 pmBSL-SEA
16h 25m1 stop
$518Delta
Find Deal
Tue, Aug 19 - Tue, Aug 26
British Airways Logo
1:30 pm - 10:55 amSEA-BSL
12h 25m1 stop
British Airways Logo
6:45 am - 11:10 amBSL-SEA
13h 25m1 stop
$533British Airways
Find Deal
Wed, Aug 20 - Tue, Aug 26
Delta Logo
6:40 pm - 9:30 amSEA-BSL
29h 50m1 stop
Delta Logo
10:10 am - 5:35 pmBSL-SEA
16h 25m1 stop
$544Delta
Find Deal
Mon, Sep 1 - Mon, Sep 15
British Airways Logo
1:30 pm - 6:20 pmSEA-BSL
19h 50m1 stop
British Airways Logo
7:20 pm - 11:10 amBSL-SEA
24h 50m1 stop
$554British Airways
Find Deal
Mon, Sep 1 - Mon, Sep 15
 Logo
5:30 am - 1:40 pmSEA-BSL
23h 10m2 stops
 Logo
6:30 pm - 11:55 amBSL-SEA
26h 25m1 stop
Mon, Sep 1 - Mon, Sep 15
United Airlines Logo
5:07 am - 7:35 pmSEA-BSL
29h 28m2 stops
United Airlines Logo
11:30 am - 2:16 pmBSL-SEA
35h 46m2 stops
$556United Airlines
Find Deal
Mon, Dec 8 - Fri, Dec 26
United Airlines Logo
5:07 am - 1:10 pmSEA-BSL
23h 03m2 stops
United Airlines Logo
1:05 pm - 9:56 pmBSL-SEA
41h 51m2 stops
$628United Airlines
Find Deal
Mon, Sep 1 - Mon, Sep 15
 Logo
4:25 pm - 7:50 amSEA-BSL
30h 25m2 stops
 Logo
8:25 am - 10:16 pmBSL-SEA
22h 51m2 stops
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KAYAK's insights & trends for Seattle to Basel flights

Get data-powered insights and trends into flights from Seattle to Basel to help you find the cheapest flights, the best time to fly and much more.

What is the cheapest month to fly from Seattle to Basel EuroAirport Swiss?

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from Seattle to Basel EuroAirport Swiss, removes the top 0.1% to account for outliers, and then takes the median of all values for each month.

The cheapest month for flights from Seattle to Basel EuroAirport Swiss is November, where tickets cost $502 (return) on average. On the other hand, the most expensive months are June and October, where the average cost of round-trip tickets is $966 and $878 respectively.

Good to know

Low seasonAugust
High seasonJuly
Cheapest flight$402
Best time to beat the crowds but there is an average 8% increase in price.
Most popular time to fly with an average 4% increase in price.
Flight from Seattle to Basel

When to book flights from Seattle to Basel

Are your dates flexible? Find out the best times to travel from Seattle to Basel based on our flight data from the last year. Discover the cheapest month and even day to fly.
Estimated round-trip price
KAYAK looks at all historical flight data for each date to provide a predicted price for one-way trips or round-trips with a duration up to 40 days. While we try to provide actual minimum prices for each date, some prices are predictions and actual prices may differ.

FAQs for booking Seattle to Basel flights

  • What is the cheapest flight from Seattle to Basel EuroAirport Swiss?

    In the last 3 days, the lowest price for a flight from Seattle to Basel EuroAirport Swiss was $402 for a one-way ticket and $513 for a round-trip.

  • Do I need a passport to fly between Seattle and Basel?

    Yes, you’ll need a passport to travel to Basel from Seattle.

  • Which aircraft models fly most regularly from Seattle to Basel?

    We unfortunately don’t have that data for this specific route.

  • Which airline alliances offer flights from Seattle to Basel?

    SkyTeam, Star Alliance, and oneworld are the airline alliances operating flights between Seattle and Basel, with Star Alliance being the most commonly used for this route.

  • Which is the best airline for flights from Seattle to Basel, Delta or Lufthansa?

    The two airlines most popular with KAYAK users for flights from Seattle to Basel are Delta and Lufthansa. With an average price for the route of $741 and an overall rating of 8.0, Delta is the most popular choice. Lufthansa is also a great choice for the route, with an average price of $649 and an overall rating of 6.7.

  • How does KAYAK find such low prices on flights from Seattle to Basel?

    KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from Seattle to Basel.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from Seattle to Basel?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to Basel from Seattle is likely to change within 7 days, so travelers know whether to wait or book now.

  • What is the Hacker Fare option on flights from Seattle to Basel?

    Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional round-trip ticket. You could then fly to Basel with an airline and back to Seattle with another airline. Booking your flights between Seattle and BSL can sometimes prove cheaper using this method.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from Seattle to Basel?

    Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying to Basel from Seattle up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

Top 3 airlines serving from Seattle to Basel

 
See real verified KAYAK customer reviews for airlines flying from Seattle to Basel. Airline scores are aggregated from all reviews left by passengers on KAYAK after flying with an airline. KAYAK doesn’t show reviews that are older than 5 years. Learn how KAYAK collects reviews.
Need help choosing which airline to fly with from Seattle to Basel? KAYAK airline reviews give an overall score for each airline based on loads of factors, including comfort, boarding, in-flight entertainment and more, to make your decision easier. See airline scores according to verified KAYAK customer reviews.
8.0
DeltaOverall score based on 7950 reviews
7.3Food
8.2Boarding
7.9Entertainment
7.9Comfort
8.5Crew
Airline reviews

Great overall. There was a bit of turbulence so they could only serve water because too much turbulence for the carts. Was glad they prioritized safety though

10.0 ExcellentTim, Jun 2025MSP - BUF
Read more Delta reviews

Great overall. There was a bit of turbulence so they could only serve water because too much turbulence for the carts. Was glad they prioritized safety though

Excellent flight, the planes were newer, they did a nice job with boarding, great service overall.

Flight was delayed long enough that I was misding my connecting flight. The agents could not get me on a comparable flight, nor could they get me s Main Cabin seat I had paid for, nor could they get me on a comparable connecting flight. The gate agent would not issue meal vouchers, even though I was delayed over six hours! I had to spend over an hour and 15 minutes with customer service on the phone to See if they could get me on a better flight and get a meal voucher. Customer service was not helpful enough in trying to find alternate flights and it Ended up taking me 24 hours for a 12 hour trip!! Delta does not provide upgrades NOR will they even give you a pass for a few hours to their lounge. They claim that they do not issue daily passes to their lounge anymore. I call BS since this would be no extra cost to them to provide excellent customer service and give you a few hours to relax in comfort when you’re sitting in a crowded airport and your flight has been screwed up for that many hours.

Great service. Flight was delayed while we sat on the runway for a couple of hours. Weather related. Staff made is very bearable. The steward servicing the first class cabin was exceptional. Thank you! 💗

5 hours of delay that could've been much shorter if Delta had taken the 1 hour delay they imposed on the flight before boarding to run any of the plane checks required for flight to find the hydraulic issue that required nearly 3 hours to fix. $24 of meal credit buys a sandwich and a soft drink. Poor communication within the terminal about what gate we'd be re-boarding from and when we'd be re-boarding.

Great flight! Only complaint I had was that I didn’t get breakfast that morning because I don’t eat eggs for breakfast.. I ate an energy bar I bought in the airport which I had never done before. Otherwise, another great Delta flight!

Amazing flight! I have never noticed the uniforms of the attendants before in twenty years of flying except today when one female had the most amazing dress on. It was beautifully designed and showed she was in charge. I never dreamed I would google who designed Delta uniforms . The ultimate compliment is when another woman admires your outfit. . I hope your designer puts it on the market

It would be nice if was given wires ear buds. Overall was a good experience was able to sleep on the plane

My flight was 6 pm 6/6. Every hour they delayed it again - air condition issues then no pilot then the crew had worked too many hours and cancelled the flight at 11 pm. Sent customers to NJ a 45 minutes uber ride to a hotel. Had to be back by 5 am for a 7 am flight and again no pilot etc with another three hours of delays.

The entertainment and wifi mostly didn't work on this flight.

Flight was 1.5 hours late to depart so changed flights to Swiss Air.

The United Airlines crew that operated this flight was subpar. They didn’t

Very small and uncomfortable seats, Hard to hear entertainment system sound. Horrible food. Staff doesn't care much about the passengers. 2nd time they didn't give me my vegetarian meal. They asked me regular food with meat. The airline and staff was from United airlines.

Checkin took along timen only.few angents available at.checkin desk. Customer support over phone no existence

At baggage claim, I was given the wrong printed ticket. The ticket belonged to another passenger for a different flight — to Zurich instead of Frankfurt (layover). I was even allowed to pass security, and when I asked the Lufthansa employee if I was on the correct flight, and why it was changed. The employee said everything was correct and I should board. When I got on the plane, there was someone in my seat, and the crew on the plane finally realized that I was on the wrong plane. When I got off the plane, nobody was willing to help, and the security refused to provide my original printed ticket. That was until I showed them that I took a photo of the ticket; once they realized I had photographic evidence, they were suddenly ready to help me. The Lufthansa employee began communicating with other airlines and found a flight that would take me to my destination via Polish Airlines. I was required to once again go through security, re-check my bag, and once again pay for my checked bag and weight overage fees. This experience was incredibly stressful and very frustrating, as you can imagine. A Lufthansa employee told me I would be eligible for a refund. Please tell me what steps I need to take in order to make that happen. Thank you!

The row of seats were so cramped it was difficult to get in and out of your seat. I even upgraded. A long flight and sad accommodations 😵‍💫 the shorter flight was very comfortable and the seating was spacious

I bought a ticket and paid for for our luggage but I had to pay for my luggage again. I’m so disappointed! We had a 30 min delay and because of that we missed our connecting flight and were told that we would be on the next flight (9am flight ) but we were landed we were booked at 12pm flight. I had a little baby w me, it was very stressful. I begged to leave at 10 am at least. I was emailed that we get a voucher but they didn’t work when we were at a breakfast store. I’ve been always happy w Lufthansa but this time was awful.

Good service … bus transfer upon arrival from plane to terminal: atrocious!!!

helpful and friendly. The Lufthanza people I dealt with before my holiday were so unhelpful by comparison.

I’m glad the bus waited for me to connect me to my next flight since we were delayed. Flight was good.

The payment system was not working so was unable to connect wifi the entire flight

everything to do with KAYAK was terrible. Your customer facing departments are utterly useless, timewasting and unhelpful.

I ordered short ribs for main course. It tasted sweet, really sweet. Horrible.

Our luggage didn’t arrive with us, that puts a damper on the whole trip.

The screen didn’t work and I didn’t get the seat upgrade I paid $300 for. They were no help with that,

Paid $180 for seat selection, and selection essnt honored. Have to call for a refund.

Was 3 hrs delayed and my poor friend I met in Barcelona was waiting at airport for 3 hrs. Dallas airport was awful

The internet was horrible. Plus they charged me $25 for service that didn't work which should have been free since I'm Concierge Key. The flight attendant Rick Young was excellent. Greeted me by name and very attentive.

Not good. First time flying AA in years and won’t be doing so again. We departed late and missed our connecting flight to Barcelona. As a result we missed the first two days of a Mediterranean cruise. No reason given for the delay. Got rerouted from JFK to Heathrow and then to Barcelona. Flight to Heathrow was delayed causing us to miss the flight to Barcelona again. Routed then to Palmero where we had to purchase transportation and a 2 night hotel stay to pick up the cruise there. Probably cost us $2k plus.

My flights were great and the crew on them was lovely especially the London to Barcelona flight as Al & AJ were so amazingly nice. I wish they would be my crew always as they have the best customer service. Sadly both flights were delayed the first one from Vegas was because they clearly loaded the cargo wrong the plane was off balance making us 2 hours late. This made me miss my connection and sadly it was challenging rebooking while I was on the flight. I will never use Kayak again as there was no customer service number or live chat and you rebooked me on a flight 2 days later. I had my mom call BA to change it which she did after spending an hour on hold. This should not be so difficult. My second flight was an hour delayed due to not being able to disconnect the bridge from the plane but I did finally make it home.

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