For quick check-in, verify your airline’s terminal before arriving. Terminals are spread out, and only some are linked by indoor walkways.

Most accurate provider | CheapOair 3 stars |
|---|---|
Most trusted provider | CheapOair 3 stars |
Round-trip from | $257 (Alaska Airlines) |
One-way from | $146 (Kiwi.com) |
Popular in | June |
Cheapest in | October |
Average price | $412 |
Good round-trip deal | $365 or less |
Good one-way deal | $216 or less |
Fly from
Fly to
Route
Depart
Return
Price
PhiladelphiaSeattle
PHL - SEA
PHLSEA
Philadelphia
Wed 12/3
6:54 pm-10:12 pm
Nonstop6h 18m
Seattle/Tacoma Intl
Sat 12/6
9:44 am-5:53 pm
Nonstop5h 09m
PhiladelphiaSeattle
PHL - SEA
PHLSEA
Philadelphia
Sat 3/7
6:20 pm-9:33 pm
Nonstop6h 13m
Seattle/Tacoma Intl
Wed 3/11
9:18 am-5:22 pm
Nonstop5h 04m
PhiladelphiaSeattle
PHL - SEA
PHLSEA
Philadelphia
Sun 3/1
6:20 pm-9:33 pm
Nonstop6h 13m
Seattle/Tacoma Intl
Sat 3/7
9:16 am-5:20 pm
Nonstop5h 04m
PhiladelphiaSeattle
PHL - SEA
PHLSEA
Philadelphia
Fri 1/23
6:00 am-10:47 am
1 stop7h 47m
Seattle/Tacoma Intl
Thu 1/29
11:25 am-11:14 pm
1 stop8h 49m
PhiladelphiaSeattle
PHL - SEA
PHLSEA
Philadelphia
Fri 1/30
7:06 pm-10:29 pm
Nonstop6h 23m
Seattle/Tacoma Intl
Sat 1/31
9:54 am-6:03 pm
Nonstop5h 09m
PhiladelphiaSeattle
PHL - SEA
PHLSEA
Philadelphia
Tue 12/9
12:45 pm-7:22 pm
1 stop9h 37m
Seattle/Tacoma Intl
Tue 12/16
7:00 am-7:41 pm
1 stop9h 41m
PhiladelphiaSeattle
PHL - SEA
PHLSEA
Philadelphia
Wed 12/10
9:39 am-2:45 pm
1 stop8h 06m
Seattle/Tacoma Intl
Mon 12/15
5:25 am-5:40 pm
1 stop9h 15m
PhiladelphiaSeattle
PHL - SEA
PHLSEA
Philadelphia
Thu 1/8
6:00 am-10:38 am
1 stop7h 38m
Seattle/Tacoma Intl
Sun 1/11
1:30 pm-11:15 pm
1 stop6h 45m
PhiladelphiaSeattle
PHL - SEA
PHLSEA
Philadelphia
Sat 3/14
6:22 pm-9:35 pm
Nonstop6h 13m
Seattle/Tacoma Intl
Thu 3/19
9:15 pm-5:23 am
Nonstop5h 08m
PhiladelphiaSeattle
PHL - SEA
PHLSEA
Philadelphia
Sat 1/17
7:06 pm-10:29 pm
Nonstop6h 23m
Seattle/Tacoma Intl
Mon 1/26
9:54 am-6:03 pm
Nonstop5h 09m
| Provider | Price Accuracy | Trust Score* |
|---|---|---|
| Price Accuracy2 stars | Trust Score*3 stars | |
| Price Accuracy3 stars | Trust Score*1 star | |
| Price Accuracy3 stars | Trust Score*3 stars | |
| Price Accuracy- | Trust Score*1 star | |
| Price Accuracy- | Trust Score*1 star | |
| Price Accuracy3 stars | Trust Score*2 stars | |
| Price Accuracy2 stars | Trust Score*3 stars | |
| Price Accuracy3 stars | Trust Score*3 stars | |
| Price Accuracy3 stars | Trust Score*3 stars | |
| Price Accuracy1 star | Trust Score*3 stars |
The best time to book flights from Philadelphia to Seattle is 71 days before your desired departure date. The cost of your flight will likely increase significantly if you book two weeks in advance of your flight.
Currently, October is the cheapest month in which you can book a flight from Philadelphia to Seattle (average of $148). Flying from Philadelphia to Seattle in December is currently the most expensive (average of $247). 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.
One of the essential ways to save on airfare from Philadelphia to Seattle is to remain as flexible as possible. Flights that are in the morning tend to be the most expensive. A flight at noon could potentially save you up to 20% on airfare.
Travelers seeking maximum savings on their Philadelphia to Seattle flight should consider departing on Tuesday at noon when fares are most often at their lowest. Sunday mornings flights should be avoided if possible as fares are typically the most expensive at this time.
About 19% of weekly flights between Philadelphia and Seattle have experienced delays in the past year, with the average delay time being 156 minutes.
Historically, flights departing in the morning are less likely to be delayed, whereas flights leaving in the evening tend to experience delays more often.
Wednesday tends to have the lowest number of delays on this route, whereas Friday has historically faced a higher average of delays compared to other days of the week.
Over the last year, Delta have had the lowest number of delays on this route, with no flights being classified as delayed.
Comfort
Crew
Food
Boarding
Entertainment
Overall
Reviews
Anonymous,Aug 2025
MFR - SEA
Comfort
Crew
Food
Boarding
Entertainment
Overall
Reviews
Anonymous,Aug 2025
MFR - SEA
Comfort
Crew
Food
Boarding
Entertainment
Overall
Reviews
Anonymous,Aug 2025
MFR - SEA
Comfort
Crew
Food
Boarding
Entertainment
Overall
Reviews
Anonymous,Aug 2025
MFR - SEA
Comfort
Crew
Food
Boarding
Entertainment
Overall
Reviews
Anonymous,Aug 2025
MFR - SEA
Comfort
Crew
Food
Boarding
Entertainment
Overall
Reviews
Anonymous,Aug 2025
MFR - SEA
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$127 | Average$252 | FlexibilityNo cancel fee | On-time65% | |
| Cheapest$130 | Average$295 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$233 | Average$377 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$238 | Average$361 | FlexibilityNo cancel fee | On-time83% | |
| Cheapest$257 | Average$474 | FlexibilityNo cancel fee | On-time85% | |
| Cheapest$277 | Average$490 | FlexibilityNo cancel fee | On-time75% | |
| Cheapest$277 | Average$443 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$286 | Average$449 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$294 | Average$456 | FlexibilityNo cancel fee | On-time63% |