What are the cheapest airlines to fly from Seattle to Delaware one-way?

To fly one-way, consider booking your trip with Southwest, which is currently one of the cheapest options available, starting at $154. Frontier flights start at $156 while deals on Delta start at $157 one-way.

In terms of precipitation, rainfall in Delaware ranges from 2.9 - 4.3 inches per month. July is typically the wettest month, when rainfall can reach 4.3 in. February is typically the driest time to visit Delaware when rainfall is around 2.9 in.

If weather is an important factor for your trip to Delaware, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 77.0 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 32.0 F).

How far in advance should I book a flight from Seattle to Delaware?

Users have found that booking a flight from Seattle to Delaware at least 55 days early can save you up to 96% on average compared to booking a flight this week. If booking 55 days before your flight isn’t an option for you, users have found flights from Seattle to Delaware for as little as $587 when booking for a departure date within the next two weeks. You can also check prices now. Some users have found airline tickets as low as $689 for flights departing within the next 3 days.

What is the cheapest month to fly from Seattle to Delaware?

Our data shows that March tends to be the cheapest month to fly to Delaware from Seattle. Users have commonly found prices around $453 for the month, but tickets can be as low as $284. Due to multiple factors, prepare for potentially higher prices in December.

What is the cheapest time of day to fly from SEA to DE?

Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Seattle to Delaware as you normally would.

What airport do you fly from for flights from Seattle to Delaware?

Most people fly from Seattle/Tacoma Intl (SEA) if they book a flight from Seattle to Delaware. Seattle/Tacoma Intl is conveniently located just 11.4 mi from Seattle’s city center.

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

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

How can I find direct flights from Seattle to Delaware?

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

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

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

$154+ Flights from Seattle to Delaware

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Cheap flight deals from Seattle to Delaware

Round-trip from	$277 (Delta)
One-way from	$154 (Southwest)
Popular in	December
Cheapest in	March
Average price	$486

From Seattle/Tacoma Intl to Delaware

Search Deals

One-way flight from Seattle/Tacoma Intl to Delaware

Search Deals

Highest demand for flights based on searches. 5% potential increase in price ($25 potential increase over avg. RT price).

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Cheapest flight prices on average. 2% potential price decrease ($12 potential savings vs. average RT price).

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Average for round-trip flights in August 2025

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Find flight deals from Seattle to Delaware

Cheapest flights from Seattle to Delaware
Explore the most affordable flight options available from Seattle to Delaware. Find the lowest fares from popular airlines and budget airlines, with prices last updated on August 13, 2025.

Wed 10/111:40 pmSEA - PHL

1 stop7h 54mDelta

Tue 10/217:00 pmPHL - SEA

1 stop7h 57mDelta

Deal found 8/11

$277

Thu 9/411:05 pmSEA - PHL

Nonstop5h 04mAmerican Airlines

Wed 9/106:50 pmPHL - SEA

Nonstop6h 14mAmerican Airlines

Deal found 8/11

$278

Wed 9/172:00 pmSEA - PHL

1 stop7h 21mUnited Airlines

Tue 9/233:00 pmPHL - SEA

2 stops10h 20mUnited Airlines

Deal found 8/12

$282

Mon 10/2010:16 amSEA - PHL

1 stop12h 25mFrontier

Thu 10/236:42 amPHL - SEA

1 stop8h 25mFrontier

Deal found 8/11

$283

Thu 10/231:02 pmSEA - PHL

1 stop13h 17mFrontier

Mon 10/276:42 amPHL - SEA

1 stop8h 25mFrontier

Deal found 8/11

$285

Sat 11/15:45 amSEA - PHL

1 stop6h 55mSouthwest

Wed 11/124:55 pmPHL - SEA

1 stop9h 00mSouthwest

Deal found 8/11

$286

Tue 9/96:10 amSEA - PHL

1 stop8h 54mDelta

Sun 9/216:00 amPHL - SEA

1 stop7h 45mDelta

Deal found 8/11

$287

Wed 9/311:11 amSEA - PHL

2 stops10h 10mUnited Airlines

Sat 9/65:15 pmPHL - SEA

1 stop8h 05mUnited Airlines

Deal found 8/13

$292

Thu 9/186:12 amSEA - PHL

1 stop15h 45mFrontier

Thu 9/256:45 amPHL - SEA

1 stop20h 45mFrontier

Deal found 8/13

$293

Thu 9/256:12 amSEA - PHL

1 stop15h 45mFrontier

Sat 10/116:42 amPHL - SEA

1 stop8h 25mFrontier

Deal found 8/12

$294

Wed 9/107:00 amSEA - PHL

1 stop13h 43mMultiple Airlines

Tue 9/237:22 amPHL - SEA

Nonstop5h 56mMultiple Airlines

Deal found 8/12

$295

Thu 9/45:49 pmSEA - PHL

1 stop8h 56mDelta

Fri 9/126:25 pmPHL - SEA

1 stop8h 29mDelta

Deal found 8/12

$297

Best flights from Seattle to Delaware
Discover carefully curated flight deals from Seattle to Delaware that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated August 13, 2025.

Wed 9/39:45 pmSEA - PHL

Nonstop5h 17mAlaska Airlines

Tue 9/96:57 pmPHL - SEA

Nonstop6h 03mAlaska Airlines

Deal found 8/11

$277

Fri 10/109:23 pmSEA - PHL

Nonstop5h 17mHawaiian Airlines

Sun 10/127:00 amPHL - SEA

Nonstop5h 49mHawaiian Airlines

Deal found 8/12

$277

Fri 10/179:23 pmSEA - PHL

Nonstop5h 17mAlaska Airlines

Fri 10/247:11 pmPHL - SEA

Nonstop6h 21mAlaska Airlines

Deal found 8/11

$277

Wed 10/89:23 pmSEA - PHL

Nonstop5h 17mAlaska Airlines

Mon 10/137:00 amPHL - SEA

Nonstop5h 49mAlaska Airlines

Deal found 8/10

$277

Tue 10/219:23 pmSEA - PHL

Nonstop5h 17mAlaska Airlines

Sat 10/257:00 amPHL - SEA

Nonstop5h 49mAlaska Airlines

Deal found 8/11

$277

Sat 9/279:45 pmSEA - PHL

Nonstop5h 17mAlaska Airlines

Tue 10/147:00 amPHL - SEA

Nonstop5h 49mAlaska Airlines

Deal found 8/12

$277

Sat 10/48:34 amSEA - SBY

1 stop7h 50mAmerican Airlines

Tue 10/76:03 amSBY - SEA

1 stop8h 27mAmerican Airlines

Deal found 8/11

$744

Mon 9/89:45 pmSEA - PHL

Nonstop5h 17mAlaska Airlines

Sat 9/137:22 amPHL - SEA

Nonstop5h 56mAlaska Airlines

Deal found 8/12

$277

Wed 10/19:45 pmSEA - PHL

Nonstop5h 17mAlaska Airlines

Mon 10/67:11 pmPHL - SEA

Nonstop6h 21mAlaska Airlines

Deal found 8/10

$277

Fri 9/59:45 pmSEA - PHL

Nonstop5h 17mAlaska Airlines

Wed 9/107:22 amPHL - SEA

Nonstop5h 56mAlaska Airlines

Deal found 8/11

$277

Fri 10/179:23 pmSEA - PHL

Nonstop5h 17mAlaska Airlines

Mon 10/277:02 amPHL - SEA

Nonstop6h 11mAlaska Airlines

Deal found 8/11

$277

Fri 10/179:23 pmSEA - PHL

Nonstop5h 17mAlaska Airlines

Wed 10/297:02 amPHL - SEA

Nonstop6h 11mAlaska Airlines

Deal found 8/11

$277

Last-minute flights from Seattle to Delaware
Discover last-minute flight deals from Seattle to Delaware. Data last updated August 13, 2025 and is based on user searches.

Mon 8/187:48 pmSEA - PHL

2 stops13h 16mFrontier

Thu 9/46:45 amPHL - SEA

1 stop20h 45mFrontier

Deal found 8/12

$361

Tue 8/196:41 amSEA - PHL

2 stops30h 49mFrontier

Thu 8/216:25 amPHL - SEA

1 stop30h 09mFrontier

Deal found 8/11

$331

Wed 8/206:41 amSEA - PHL

1 stop19h 13mFrontier

Fri 8/227:00 pmPHL - SEA

2 stops28h 51mFrontier

Deal found 8/12

$368

Thu 8/216:17 amSEA - PHL

2 stops15h 52mFrontier

Mon 8/256:25 amPHL - SEA

1 stop21h 09mFrontier

Deal found 8/11

$348

Thu 8/2111:55 pmSEA - PHL

1 stop8h 19mMultiple Airlines

Mon 8/256:25 amPHL - SEA

1 stop21h 09mMultiple Airlines

Deal found 8/13

$380

Fri 8/224:40 pmSEA - PHL

2 stops28h 40mFrontier

Mon 8/256:25 amPHL - SEA

1 stop21h 09mFrontier

Deal found 8/12

$336

Sat 8/236:25 amSEA - PHL

2 stops14h 55mMultiple Airlines

Sat 8/306:58 pmPHL - SEA

Nonstop6h 02mMultiple Airlines

Deal found 8/11

$340

Sat 8/236:25 amSEA - PHL

2 stops14h 55mFrontier

Sun 8/248:27 pmPHL - SEA

2 stops16h 07mFrontier

Deal found 8/12

$379

Wed 8/276:41 amSEA - PHL

1 stop19h 13mFrontier

Tue 9/26:37 pmPHL - SEA

2 stops31h 24mFrontier

Deal found 8/13

$302

Wed 9/311:11 amSEA - PHL

2 stops10h 10mUnited Airlines

Sat 9/65:15 pmPHL - SEA

1 stop8h 05mUnited Airlines

Deal found 8/13

$292

Wed 9/36:41 amSEA - PHL

2 stops23h 44mFrontier

Sat 9/66:45 amPHL - SEA

1 stop16h 54mFrontier

Deal found 8/11

$299

Thu 9/411:05 pmSEA - PHL

Nonstop5h 04mAmerican Airlines

Wed 9/106:50 pmPHL - SEA

Nonstop6h 14mAmerican Airlines

Deal found 8/11

$278

One-way flights from Seattle to Delaware
Search for one-way flight options from Seattle to Delaware. Find affordable one-way fares based on user searches. Data last updated August 13, 2025.

Sat 9/69:10 pmSEA - PHL

2 stops11h 40mSouthwest

Deal found 8/10

$154

Thu 8/284:40 pmSEA - PHL

1 stop9h 14mFrontier

Deal found 8/11

$156

Fri 9/127:30 pmSEA - PHL

1 stop7h 15mDelta

Deal found 8/12

$157

Tue 11/116:00 amSEA - PHL

2 stops14h 55mFrontier

Deal found 8/10

$158

Fri 9/129:45 pmSEA - PHL

Nonstop5h 17mAlaska Airlines

Deal found 8/11

$159

Wed 9/105:15 amSEA - PHL

2 stops9h 25mSouthwest

Deal found 8/11

$164

Sun 10/127:18 pmSEA - PHL

1 stop7h 32mDelta

Deal found 8/13

$169

Wed 10/111:10 amSEA - PHL

2 stops10h 35mUnited Airlines

Deal found 8/11

$170

Sun 9/2111:54 pmSEA - PHL

1 stop9h 02mUnited Airlines

Deal found 8/12

$172

Fri 8/224:40 pmSEA - PHL

1 stop9h 14mFrontier

Deal found 8/11

$173

Thu 9/116:12 amSEA - PHL

2 stops12h 20mFrontier

Deal found 8/11

$174

Fly from

Fly to

Route

Depart

Return

Price

SeattlePhiladelphia

SEA - PHL

SEAPHL

Seattle/Tacoma Intl

Wed 9/3

9:45 pm-6:02 am

Nonstop5h 17m

Philadelphia

Tue 9/9

6:57 pm-10:00 pm

Nonstop6h 03m

$277

SeattlePhiladelphia

SEA - PHL

SEAPHL

Seattle/Tacoma Intl

Fri 10/10

9:23 pm-5:40 am

Nonstop5h 17m

Philadelphia

Sun 10/12

7:00 am-9:49 am

Nonstop5h 49m

$277

SeattlePhiladelphia

SEA - PHL

SEAPHL

Seattle/Tacoma Intl

Fri 10/17

9:23 pm-5:40 am

Nonstop5h 17m

Philadelphia

Fri 10/24

7:11 pm-10:32 pm

Nonstop6h 21m

$277

SeattlePhiladelphia

SEA - PHL

SEAPHL

Seattle/Tacoma Intl

Wed 10/8

9:23 pm-5:40 am

Nonstop5h 17m

Philadelphia

Mon 10/13

7:00 am-9:49 am

Nonstop5h 49m

$277

SeattlePhiladelphia

SEA - PHL

SEAPHL

Seattle/Tacoma Intl

Tue 10/21

9:23 pm-5:40 am

Nonstop5h 17m

Philadelphia

Sat 10/25

7:00 am-9:49 am

Nonstop5h 49m

$277

SeattlePhiladelphia

SEA - PHL

SEAPHL

Seattle/Tacoma Intl

Sat 9/27

9:45 pm-6:02 am

Nonstop5h 17m

Philadelphia

Tue 10/14

7:00 am-9:49 am

Nonstop5h 49m

$277

SeattlePhiladelphia

SEA - PHL

SEAPHL

Seattle/Tacoma Intl

Mon 9/8

9:45 pm-6:02 am

Nonstop5h 17m

Philadelphia

Sat 9/13

7:22 am-10:18 am

Nonstop5h 56m

$277

SeattlePhiladelphia

SEA - PHL

SEAPHL

Seattle/Tacoma Intl

Wed 10/1

9:45 pm-6:02 am

Nonstop5h 17m

Philadelphia

Mon 10/6

7:11 pm-10:32 pm

Nonstop6h 21m

$277

SeattlePhiladelphia

SEA - PHL

SEAPHL

Seattle/Tacoma Intl

Fri 9/5

9:45 pm-6:02 am

Nonstop5h 17m

Philadelphia

Wed 9/10

7:22 am-10:18 am

Nonstop5h 56m

$277

SeattlePhiladelphia

SEA - PHL

SEAPHL

Seattle/Tacoma Intl

Fri 10/17

9:23 pm-5:40 am

Nonstop5h 17m

Philadelphia

Mon 10/27

7:02 am-10:13 am

Nonstop6h 11m

$277

Flights are sorted by cheapest round-trip flights first.

Deals found on 8/10

Showing 1-10 of 25 results

Best time to book a flight from Seattle to Delaware

Have a flexible travel schedule? Discover the best time to fly to Delaware from Seattle 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.

Cheapflights Insights

Everything you need to know about your flight from Seattle to Delaware

No data available for this route at this time. Please check back soon.

Related info for your journey

What airport do you fly from for flights from Seattle to Delaware?
Most people fly from Seattle/Tacoma Intl (SEA) if they book a flight from Seattle to Delaware. Seattle/Tacoma Intl is conveniently located just 11.4 mi from Seattle’s city center.
What are the cheapest airlines to fly from Seattle to Delaware one-way?
To fly one-way, consider booking your trip with Southwest, which is currently one of the cheapest options available, starting at $154. Frontier flights start at $156 while deals on Delta start at $157 one-way.
Can I find deals for flights from Seattle to Delaware that include hotel bookings?
Yes. In addition to deals on Seattle to Delaware flights, Cheapflights offers vacation packages that include both flights and hotel.
How can I find direct flights from Seattle to Delaware?
After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Seattle to Delaware.
Can I find deals for business class flights from Seattle to Delaware?
Yes. Cheapflights offers flight deals from Seattle to Delaware by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

See more FAQs

Browse thousands of different options on Cheapflights for your next trip

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$154+ Cheap flights from Seattle (SEA) to Delaware

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 9/6. Fares are subject to change and may not be available on all flights or dates of travel.

Find cheap flights from Seattle to Delaware with Cheapflights

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Cheap flight deals from Seattle to Delaware

Keep the following information in mind while searching for Seattle to Delaware flight deals. Data was last updated August 13, 2025.

Round-trip from

One-way from

Popular in

Cheapest in

Average price

Find flight deals from Seattle to Delaware

Cheapest flights from Seattle to DelawareExplore the most affordable flight options available from Seattle to Delaware. Find the lowest fares from popular airlines and budget airlines, with prices last updated on August 13, 2025.

Explore the most affordable flight options available from Seattle to Delaware. Find the lowest fares from popular airlines and budget airlines, with prices last updated on August 13, 2025.

Cheapflights Fare Finder

Use the filters below to find and compare flights from Seattle to Delaware that are best for you.

Best time to book a flight from Seattle to Delaware

Have a flexible travel schedule? Discover the best time to fly to Delaware from Seattle with our price prediction graph.

Cheapflights Insights

Everything you need to know about your flight from Seattle to Delaware

Related info for your journey

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

What airport do you fly from for flights from Seattle to Delaware?

What are the cheapest airlines to fly from Seattle to Delaware one-way?

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

How can I find direct flights from Seattle to Delaware?

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

Browse thousands of different options on Cheapflights for your next trip

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Alternative routes for Seattle to Delaware

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Cheapest flights from Seattle to Delaware
Explore the most affordable flight options available from Seattle to Delaware. Find the lowest fares from popular airlines and budget airlines, with prices last updated on August 13, 2025.