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$539+ Cheap flights from Basel EuroAirport Swiss (BSL) to Seattle (SEA)

This is the cheapest round-trip flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 12/5. Fares are subject to change and may not be available on all flights or dates of travel.
BSL — SEA
oct. 17 — oct. 241
vie. 10/17
vie. 10/24
1 adult, Economy
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Cheap flight deals from Basel to Seattle

Discover tips and strategies to find the most affordable flight options for your journey from Basel (BSL) to Seattle (SEA). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated septiembre 17, 2025.

Round-trip from

$539
(British Airways)

Popular in

July

Cheapest in

November

Average price

$543
From Basel EuroAirport Swiss to Seattle/Tacoma Intl
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Highest demand for flights based on searches. 20% potential increase in price ($168 potential increase over avg. RT price).
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Cheapest flight prices on average. 6% potential price decrease ($42 potential savings vs. average RT price).
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Average for round-trip flights in September 2025
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Find flight deals from Basel to Seattle

Cheapest flights from Basel to Seattle
Explore the most affordable flight options available from Basel to Seattle. Find the lowest fares from popular airlines and budget airlines, with prices last updated on septiembre 17, 2025.

This British Airways deal was found by Cheapflights users on 9/17. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure British Airways is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
vie. 12/57:50 pmBSL - SEA
1 stop24h 40mBritish Airways
mar. 12/99:00 amSEA - BSL
2 stops21h 05mBritish Airways
Deal found 9/17$539
This British Airways deal was found by Cheapflights users on 9/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure British Airways is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
jue. 11/611:05 amBSL - SEA
2 stops21h 13mBritish Airways
lun. 11/102:46 pmSEA - BSL
2 stops18h 29mBritish Airways
Deal found 9/15$541
This American Airlines deal was found by Cheapflights users on 9/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
jue. 11/611:05 amBSL - SEA
2 stops21h 13mAmerican Airlines
lun. 11/1011:42 amSEA - BSL
2 stops17h 53mAmerican Airlines
Deal found 9/15$549
This KLM deal was found by Cheapflights users on 9/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure KLM is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
lun. 9/222:25 pmBSL - SEA
1 stop30h 20mKLM
mié. 10/15:40 pmSEA - BSL
1 stop15h 10mKLM
Deal found 9/15$566
This Delta deal was found by Cheapflights users on 9/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
lun. 9/226:15 amBSL - SEA
2 stops18h 51mDelta
mié. 10/15:40 pmSEA - BSL
1 stop15h 10mDelta
Deal found 9/15$572
This KLM deal was found by Cheapflights users on 9/17. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure KLM is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
vie. 12/511:15 amBSL - SEA
1 stop33h 35mKLM
mar. 12/93:05 pmSEA - BSL
1 stop34h 35mKLM
Deal found 9/17$578
This TUI fly deal was found by Cheapflights users on 9/17. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure TUI fly is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
vie. 12/56:05 amBSL - SEA
2 stops19h 48mAir France
mar. 12/97:35 amSEA - BSL
2 stops17h 15mAir France
Deal found 9/17$587
This United Airlines deal was found by Cheapflights users on 9/17. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
jue. 12/189:50 amBSL - SEA
2 stops22h 09mUnited Airlines
vie. 1/211:39 pmSEA - BSL
2 stops51h 51mUnited Airlines
Deal found 9/17$663
This Air France deal was found by Cheapflights users on 9/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Air France is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
jue. 12/185:55 pmBSL - SEA
1 stop26h 55mAir France
vie. 1/22:10 pmSEA - BSL
1 stop34h 40mAir France
Deal found 9/15$718
This Delta deal was found by Cheapflights users on 9/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
jue. 12/186:05 amBSL - SEA
1 stop14h 45mDelta
vie. 1/210:40 amSEA - BSL
2 stops15h 00mDelta
Deal found 9/15$728

Cheapflights Fare Finder

 
Customize your flight search to find flights from Basel to Seattle that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated septiembre 17, 2025.
Use the filters below to find and compare flights from Basel EuroAirport Swiss to Seattle that are best for you.

Fly from

Basel

Fly to

Seattle

Route

Depart

Return

Price

BaselSeattle

BSL - SEA

BSLSEA

Basel EuroAirport Swiss

vie. 12/5

7:50 pm-11:30 am

1 stop24h 40m

Seattle/Tacoma Intl

mar. 12/9

9:00 am-3:05 pm

2 stops21h 05m

$539

BaselSeattle

BSL - SEA

BSLSEA

Basel EuroAirport Swiss

jue. 11/6

11:05 am-11:18 pm

2 stops21h 13m

Seattle/Tacoma Intl

lun. 11/10

2:46 pm-6:15 pm

2 stops18h 29m

$541

BaselSeattle

BSL - SEA

BSLSEA

Basel EuroAirport Swiss

jue. 11/6

6:05 am-11:45 am

1 stop14h 40m

Seattle/Tacoma Intl

lun. 11/10

9:43 am-5:25 pm

2 stops22h 42m

$566

BaselSeattle

BSL - SEA

BSLSEA

Basel EuroAirport Swiss

lun. 9/22

2:25 pm-11:45 am

1 stop30h 20m

Seattle/Tacoma Intl

mié. 10/1

5:40 pm-5:50 pm

1 stop15h 10m

$566

BaselSeattle

BSL - SEA

BSLSEA

Basel EuroAirport Swiss

lun. 9/22

6:15 am-4:06 pm

2 stops18h 51m

Seattle/Tacoma Intl

mié. 10/1

11:15 am-1:10 pm

2 stops16h 55m

$566

BaselSeattle

BSL - SEA

BSLSEA

Basel EuroAirport Swiss

vie. 12/5

11:15 am-11:50 am

1 stop33h 35m

Seattle/Tacoma Intl

mar. 12/9

3:05 pm-10:40 am

1 stop34h 35m

$578

BaselSeattle

BSL - SEA

BSLSEA

Basel EuroAirport Swiss

vie. 12/5

6:05 am-4:53 pm

2 stops19h 48m

Seattle/Tacoma Intl

mar. 12/9

7:35 am-9:50 am

2 stops17h 15m

$587

BaselSeattle

BSL - SEA

BSLSEA

Basel EuroAirport Swiss

lun. 9/22

8:25 am-8:42 pm

2 stops21h 17m

Seattle/Tacoma Intl

mié. 10/1

6:50 pm-7:35 pm

1 stop15h 45m

$1,009

BaselSeattle

BSL - SEA

BSLSEA

Basel EuroAirport Swiss

jue. 11/6

2:30 pm-5:00 pm

3 stops35h 30m

Seattle/Tacoma Intl

lun. 11/10

8:00 pm-12:30 pm

2 stops31h 30m

$1,202

BaselSeattle

BSL - SEA

BSLSEA

Basel EuroAirport Swiss

dom. 9/21

9:40 pm-10:59 pm

3 stops58h 19m

$578

Flights are sorted by cheapest round-trip flights first.

Deals found on 9/16

Showing 1-10 of 13 results
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Best time to book a flight from Basel to Seattle

Have a flexible travel schedule? Discover the best time to fly to Seattle from Basel with our price prediction graph.
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Related info for your journey

Find useful and relevant information for your journey from Basel to Seattle. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • How long is the flight from Basel EuroAirport Swiss to Seattle?

    Departing from Basel EuroAirport Swiss to Seattle will take you 14h 40m. Airlines will cover a distance of 5207 mi. This flight may include one or multiple stops.

  • Can I find deals for flights from Basel to Seattle that include hotel bookings?

    Yes. In addition to deals on Basel to Seattle flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Basel to Seattle?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Basel to Seattle.

  • Can I find deals for business class flights from Basel to Seattle?

    Yes. Cheapflights offers flight deals from Basel to Seattle by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

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

    Currently, January is the cheapest month in which you can book a flight from Basel EuroAirport Swiss to Seattle (average of $238). Flying from Basel EuroAirport Swiss to Seattle in June is currently the most expensive (average of $387). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

Traveling to a place near Seattle?

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