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 (Delta) |
One-way from | $144 (United Airlines) |
Popular in | June |
Cheapest in | October |
Average price | $422 |
Good round-trip deal | $356 or less |
Good one-way deal | $240 or less |
Fly from
Fly to
Route
Depart
Return
Price
PhiladelphiaSeattle
PHL - SEA
PHLSEA
Philadelphia
Mon 1/12
8:35 am-3:44 pm
1 stop10h 09m
Seattle/Tacoma Intl
Thu 1/15
7:00 am-5:34 pm
1 stop7h 34m
PhiladelphiaSeattle
PHL - SEA
PHLSEA
Philadelphia
Thu 1/8
5:17 pm-9:49 pm
1 stop7h 32m
Seattle/Tacoma Intl
Mon 1/12
11:10 pm-11:53 am
1 stop9h 43m
PhiladelphiaSeattle
PHL - SEA
PHLSEA
Philadelphia
Tue 2/3
2:30 pm-11:15 pm
1 stop11h 45m
Seattle/Tacoma Intl
Tue 2/10
11:10 pm-8:50 am
1 stop6h 40m
PhiladelphiaSeattle
PHL - SEA
PHLSEA
Philadelphia
Fri 2/20
6:20 pm-12:59 am
1 stop9h 39m
Seattle/Tacoma Intl
Mon 2/23
9:19 am-9:33 pm
1 stop9h 14m
PhiladelphiaSeattle
PHL - SEA
PHLSEA
Philadelphia
Sat 1/10
5:50 am-11:00 am
1 stop8h 10m
Seattle/Tacoma Intl
Mon 1/12
6:05 am-4:20 pm
1 stop7h 15m
PhiladelphiaSeattle
PHL - SEA
PHLSEA
Philadelphia
Sun 12/14
6:00 am-10:40 am
1 stop7h 40m
Seattle/Tacoma Intl
Tue 1/13
6:15 am-7:41 pm
1 stop10h 26m
PhiladelphiaSeattle
PHL - SEA
PHLSEA
Philadelphia
Tue 2/17
6:50 pm-12:09 am
1 stop8h 19m
Seattle/Tacoma Intl
Fri 2/20
6:10 am-5:56 pm
1 stop8h 46m
PhiladelphiaSeattle
PHL - SEA
PHLSEA
Philadelphia
Fri 2/20
6:50 pm-12:09 am
1 stop8h 19m
Seattle/Tacoma Intl
Mon 2/23
11:15 pm-11:43 am
1 stop9h 28m
PhiladelphiaSeattle
PHL - SEA
PHLSEA
Philadelphia
Sun 1/25
4:59 pm-11:15 pm
1 stop9h 16m
Seattle/Tacoma Intl
Wed 1/28
6:15 am-5:42 pm
1 stop8h 27m
PhiladelphiaSeattle
PHL - SEA
PHLSEA
Philadelphia
Thu 1/22
9:40 am-2:21 pm
1 stop7h 41m
Seattle/Tacoma Intl
Mon 1/26
11:10 pm-8:50 am
1 stop6h 40m
| 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 April is currently the most expensive (average of $237). 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 154 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.
Crew
Entertainment
Overall
Food
Boarding
Comfort
Reviews
Marcie,Nov 2025
PIT - SEA
Crew
Entertainment
Overall
Food
Boarding
Comfort
Reviews
Marcie,Nov 2025
PIT - SEA
Crew
Entertainment
Overall
Food
Boarding
Comfort
Reviews
Marcie,Nov 2025
PIT - SEA
Crew
Entertainment
Overall
Food
Boarding
Comfort
Reviews
Marcie,Nov 2025
PIT - SEA
Crew
Entertainment
Overall
Food
Boarding
Comfort
Reviews
Marcie,Nov 2025
PIT - SEA
Crew
Entertainment
Overall
Food
Boarding
Comfort
Reviews
Marcie,Nov 2025
PIT - SEA
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$127 | Average$250 | FlexibilityNo cancel fee | On-time65% | |
| Cheapest$134 | Average$295 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$227 | Average$375 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$238 | Average$365 | FlexibilityNo cancel fee | On-time83% | |
| Cheapest$257 | Average$474 | FlexibilityNo cancel fee | On-time85% | |
| Cheapest$276 | Average$449 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$277 | Average$491 | FlexibilityNo cancel fee | On-time75% | |
| Cheapest$277 | Average$441 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$296 | Average$456 | FlexibilityNo cancel fee | On-time63% |