$109 Find Cheap Flights from Seattle to Portsmouth

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 Portsmouth departing on 6/3. 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.
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Cheap Flight Deals from Seattle to Portsmouth (SEA-BOS)

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Seattle to Portsmouth 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.

Recent round-trip flight deals from Seattle to Portsmouth

KAYAK's recommended round-trip deals from the most popular airlines that fly from Seattle to Portsmouth.
Discover the best prices for you by selecting your travel dates on KAYAK.
Delta Logo
3:20 pm - 11:44 pmSEA-BOS
5h 24mnonstop
Delta Logo
11:00 am - 2:31 pmBOS-SEA
6h 31mnonstop
$237Delta
Find Deal
Wed, Sep 17 - Wed, Sep 24
Spirit Airlines Logo
6:00 am - 4:24 pmSEA-BOS
31h 24m2 stops
Spirit Airlines Logo
6:00 am - 12:10 amBOS-SEA
45h 10m3 stops
$239Spirit Airlines
Find Deal
Thu, May 29 - Sun, Jun 1
Alaska Airlines Logo
3:40 pm - 12:06 amSEA-BOS
5h 26mnonstop
Alaska Airlines Logo
8:40 am - 4:48 pmBOS-SEA
11h 08m1 stop
$257Alaska Airlines
Find Deal
Tue, Jun 3 - Fri, Jun 6
Alaska Airlines Logo
6:59 pm - 7:40 amSEA-BOS
9h 41m1 stop
Alaska Airlines Logo
7:00 am - 1:44 pmBOS-SEA
9h 44m1 stop
$261Alaska Airlines
Find Deal
Fri, Jun 6 - Tue, Jun 10
United Airlines Logo
11:50 pm - 11:16 amSEA-BOS
8h 26m1 stop
United Airlines Logo
6:00 am - 11:32 amBOS-SEA
8h 32m1 stop
$262United Airlines
Find Deal
Wed, May 28 - Sun, Jun 1
JetBlue Logo
11:38 am - 8:10 pmSEA-BOS
5h 32mnonstop
JetBlue Logo
7:00 am - 10:18 amBOS-SEA
6h 18mnonstop
$264JetBlue
Find Deal
Sat, May 17 - Tue, Jun 3
American Airlines Logo
12:05 am - 10:56 amSEA-BOS
7h 51m1 stop
American Airlines Logo
6:58 am - 2:18 pmBOS-SEA
10h 20m1 stop
$268American Airlines
Find Deal
Thu, Jun 5 - Tue, Jun 10
American Airlines Logo
12:05 am - 10:56 amSEA-BOS
7h 51m1 stop
American Airlines Logo
4:02 pm - 10:26 pmBOS-SEA
9h 24m1 stop
$269American Airlines
Find Deal
Thu, Jun 5 - Tue, Jun 10
JetBlue Logo
11:38 am - 8:10 pmSEA-BOS
5h 32mnonstop
JetBlue Logo
7:10 am - 10:28 amBOS-SEA
6h 18mnonstop
$280JetBlue
Find Deal
Thu, May 15 - Thu, May 29
United Airlines Logo
12:20 am - 10:57 amSEA-BOS
7h 37m1 stop
United Airlines Logo
5:30 am - 11:50 amBOS-SEA
9h 20m1 stop
$342United Airlines
Find Deal
Wed, Jun 25 - Sun, Jun 29
Useful Info

Good to know

Low seasonFebruary
High seasonAugust
Cheapest flight$109
Best time to beat the crowds with an average 24% drop in price.
Most popular time to fly with an average 31% increase in price.
Flight from Seattle to Boston

When to book flights from Seattle to Portsmouth

Are your dates flexible? Find out the best times to travel from Seattle to Portsmouth based on our flight data from the last year. Discover the cheapest month and even day to fly.
Estimated round-trip price

FAQs for booking flights from Seattle to Portsmouth

  • Which airports will I be using when flying from Seattle to Portsmouth?

    When flying out of Seattle you’ll be using Seattle/Tacoma Intl. Portsmouth does not have its own airport so you’ll be flying into nearby Boston Logan Intl airport, which is 50.3 mi away.

  • How long does a flight from Seattle to Portsmouth take?

    Direct flights cover the 2,487 miles separating Seattle and Portsmouth in about 5h 16m.

  • How many flights are there between Seattle and Portsmouth?

    38 direct flights run between Seattle and Portsmouth on a daily basis. On average, there are about 269 departures each week.

  • What’s the cheapest day of the week to fly between Seattle and Portsmouth?

    Consider leaving on a Wednesday and avoid Fridays if you are looking for the best rates. For your return to Seattle, you’ll find the best rates on Saturdays and the most expensive ones on Tuesdays.

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

    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 Portsmouth.

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

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to Portsmouth 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 Portsmouth?

    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 Portsmouth with an airline and back to Seattle with another airline.

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

    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 Portsmouth from Seattle up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

  • Which airlines provide the cheapest flights from Seattle to Portsmouth?

    In the last 72 hours, the cheapest one-way ticket between Seattle and Portsmouth found on KAYAK was with Spirit Airlines for $109. Delta offered a round-trip connection from $237 and Spirit Airlines from $239.

Top tips for finding cheap flights from Seattle to Portsmouth

  • There is no airport in Portsmouth. Instead, you’ll be flying into Boston Logan Airport when flying between Seattle and Portsmouth.
  • The cheapest flight from Seattle to Portsmouth was found 80 days before departure, on average.
  • Book at least 1 week before departure in order to get a below-average price.
  • High season is considered to be June, July and August. The cheapest month to fly is January.

Top 5 airlines serving Seattle to Portsmouth

Need help choosing which airline to fly with from Seattle to Portsmouth? 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
Alaska AirlinesOverall score based on 9972 reviews
8.1Boarding
8.5Crew
7.1Entertainment
7.1Food
7.9Comfort
Airline reviews

I made a mistake. Read what I wrote in the flight from Dulles to SEA. The negative experience was from SEA to BOI. Total garbage. Wont do it again.

2.0 MediocreAnonymous, Apr 2025SEA - BOI
Read more Alaska Airlines reviews

I made a mistake. Read what I wrote in the flight from Dulles to SEA. The negative experience was from SEA to BOI. Total garbage. Wont do it again.

Need to get on train for second flight it’s much nicer when all the gates are together for obvious reasons

Cramped, crowded aircraft. Poorly organized boarding. Tasteless crackers to eat. 40 minutes late. A standard US air travel experience.

Would not mind having movie options an available like Delta, but is not necessary. Did not have food, so cannot appropriately rate that section.

Three hour flight so snacks and basic drinks unless you pre buy as usual. Didn’t do my emtertainment as was tired after 23 hours of travel. You have to use your own device on US flights if travelers aren’t aware so if you only use your cell phone that can be small. Crew are great.

Awful. We got the last seats and they don't recline. We've been on this horrible journey since 6am and won't get to our destination almost a full day later. Oh and no food, either. Never again.

An uneventful flight is a good experience although one of the pilots gauges wasn’t working right so we had a half hour delay—no one can foresee that.

Plane was delayed and got me in past bedtime. But more importantly, my tsa precheck number wasn’t on my ticket so had to deal with the general line. Oh well, guess the delay helped that situation.

It was as good as flying can be, which is still very uncomfortable. Clean new aircraft, great crew.

Everything was good. The flight attendants were great. I was disappointed that there wasn’t any screens on the back of the seats to watch movies, tv, etc. I only had my phone to watch movies on.

Flight was delayed due to weather. Crew did a nice job of making us comfortable. No complain complaints.

Delta is my preferred airline. I've traveled with them for years. On time in most cases, good communication, easy to use app. Most planes are pretty nice. I was on a CRJ 700/900 however, which was pretty badly aged inside and needed a refresh. No infotainment, unreliable wifi, best to download before boarding or bring a book. Food choices are really just snacks on this flight, nice variety but about what you'd expect. Great staff and prompt in departure and early arrival too. Overall quite satisfied.

Crew was friendly Love the entertainment in the seat head rest.

Delta flight was on time, seats were comfortable, and crew was nice.

This had nothing to do with Delta… The flights were on time and flawless. The service was excellent. We purchased seats in (aisle/middle) comfort plus since this was a cross country flight. Unfortunately, the woman seated at the window was 300+ pounds and, as might be expected, covered up about a third of the middle seat also. there was absolutely nothing that Delta could have done about that… I just don’t know what the answer should be. If you purchase a seat, you should should be able to use the entire seat and not just the portion that someone else is not sitting/oozing in. Disappointing…there should be something that could be done….I'm just not sure what solution could be.

Delayed take-off. Very small plane so very scary with lots of bumps during the flight. Would never fly Delta on short flights in small 80 seaters plane again! Felt relieved when landed.

The worst part was I was NOT allowed in the lounge even though I was holding a first class ticket and have a premium American Express card. I have flown Business or First Class with many airlines. Delta is the ONLY one who does not extend this courtesy to anyone except people who hold the very expensive American Express card. As a result, I won’t fly Delta if I have any other choice.

A little bumpy ride . No food was being provided due the the turbulence. That was ok it was a short flight to my standards.

Simply outstanding. Their new lounge for Delta One customers is a cut above the rest.

The Dekta Rep that checked us in was great. She's very personable, pleasant, and can tell she enjoys her job.

A bit rush for transit. Food and entertainment are not available

Multiple delays and not straight answer from the United team

Stewardess spilled orange juice on my clothes/seat no help no apology just threw napkins at me to clean the mess up. Not Happy.

Smooth flight. Boarding was chaotic. Could not hear the gate agent over the intercom. People were lined up in the wrong lines. Groups one and two were told to board through line one and group 3 through line 2. All very confusing. Once in the air, the flight was smooth. There was no entertainment option on this aircraft, even though it was a larger aircraft.

The plane pushed back from the gate on time. However, it stopped on the ramp, and we waited for over 20 minutes before the aircraft pulled back to the gate. Apparently, something of importance had to be removed from the aircraft by the gate agent. I found this to be odd. The delay was not significant, but I felt that whatever was on the aircraft that had to be taken off, should’ve been done before we pushed back from the gate.

Electric plugs didn't work. Entertainment system wasn't working

The design of the light switch on the arm rest is ridiculous.

Smooth boarding process. Early departure, smooth flight, early arrival. The entertainment package has very good recent movie options. The flight crew were friendly and professional.

leg space better than expected. two washrooms for one plane isn't enough.

The gate attendant let me walk right by her with a bag too big for the overhead compartment

Excellent. Although they used to greet me as a mosaic member and provide a free drink, early boarding helps me to keep coming back to JetBlue.

Cancelled flight with no specific instructions to get a boarding pass for another flight. The whole flight of people were in line for an hour because there was only 1 person to help at the desk. This was unusual for JetBlue.

It was too hot in the cabin. The AC did not help.

Except for the 28 minute delay leaving and the earlier reschedule to a later takeoff time the flight was good.

Loved the leg room and tvs screens on the seats and free WiFi. Wish the price was lower and could save by rebooking

It took 1-1/2 hours to get our luggage after we landed. That to me is unacceptable

The flight was delayed for 4 hours. Once onboard the crew was wonderful.

Overall was excellent. Will definitely us JetBlue in the future.

I rate it is good we had a 4-hour travel delay at one point but JetBlue gave out food vouchers and travel points credits for another flight so they try to make up for it

Smooth boarding and friendly crew. Unfortunately as soon as we boarded the unit that provides air circulation failed. The pilot informed us and requested maintenance technicians to check it out. The plane became uncomfortably warm without any fresh air coming in. Plus the repair delayed our departure. I am glad the maintenance crew were able to fix the problem. I also was without use of my tv monitor for the first 1/3rd of the trip.

Pitch was very small. Knees were on the seat back in front of me.

Several delays. Next flight was worse. Did not arrive home until 2am PT

Very helpful ground crew after an earlier flight delay and being rebooked on a different flight.

Everything about the flight was lovely…We left early, arrived early, cabin crew were efficient and helpful. Flight was easy and most pleasant.

First world problems, but still… We were seated in first class and asked for a cocktail on a very short, 50 minute flight. After our drink order was taken, a half hour went by, and we noticed that every other person in the small plane had been served except for us. We got up to ask about it, the drinks finally came, then were taken away three minutes later since the flight was so short. Really strange situation, on the other hand, we were in Utah.

We missed our flight. The boarding pass had the wrong gate and by the time we received the text from Kayak, our flight was already gone. I’ll never use Kayak again and will go direct to the airlines in the future.

Boarding took forever, the plane was cramped and cold, and the seatbelt song came on constantly throughout the red eye flight with a loud pre-recorded message playing each time

Cabin felt crammed Snacks are lame But crew was super efficient getting us out on time despite delay

Took off on time and successfully avoided weather that looked to be a problem along the way

There were five broken seats on the plane. The crew was very rude in telling people they had to get off the plane and get a flight the next day. No call for volunteers, but telling people they had to get off. One woman was flying with her elderly mother and daughter and was told she had to leave or all three had to leave. Fortunately, a volunteer offered to stay. The situation was handled poorly.

Everything you need to know for your flight from Seattle to Portsmouth

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