$184 Find Cheap Flights from Seattle to Portsmouth - Compare and Save

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 10/26. 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.
1 adult
1 adult, Economy, 0 bags

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Everything you should know

Cheapest round-trip
$317
Typical prices: $240-$406
United Airlines
Fri 9/18Tue 9/22
SEA - BOS • 1 stop
Cheapest non-stop
$317
Typical prices: $302-$487
JetBlue
Wed 8/26Fri 9/11
SEA - BOS • Non-stop
Arrival airport
You can't fly directly to Portsmouth. It is served by Boston (BOS), located 50.3 miles from Portsmouth.
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Flight Deals
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Flight Deals

Cheap Flights 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.
Discover the best prices for you by selecting your travel dates on KAYAK.

Recent round-trip flight deals from Seattle to Portsmouth

Fri, Sep 18 - Tue, Sep 22
United Airlines Logo
1:57 pm - 1:10 am
SEA
-
BOS
8h 13m
1 stop
United Airlines Logo
5:01 pm - 10:45 pm
BOS
-
SEA
8h 44m
1 stop
$317United Airlines
Mon, Nov 2 - Mon, Nov 9
United Airlines Logo
6:45 am - 5:27 pm
SEA
-
BOS
7h 42m
1 stop
United Airlines Logo
6:01 pm - 12:59 am
BOS
-
SEA
9h 58m
1 stop
$317United Airlines
Wed, Aug 26 - Fri, Sep 11
JetBlue Logo
11:40 am - 8:09 pm
SEA
-
BOS
5h 29mnonstop
JetBlue Logo
7:20 pm - 10:37 pm
BOS
-
SEA
6h 17mnonstop
$317JetBlue
Wed, Aug 26 - Wed, Sep 2
JetBlue Logo
11:40 am - 8:09 pm
SEA
-
BOS
5h 29mnonstop
JetBlue Logo
12:57 pm - 9:08 pm
BOS
-
SEA
11h 11m
1 stop
$317JetBlue
Sun, Sep 20 - Mon, Oct 5
American Airlines Logo
11:57 pm - 12:39 pm
SEA
-
BOS
9h 42m
1 stop
American Airlines Logo
4:48 pm - 12:36 am
BOS
-
SEA
10h 48m
1 stop
$317American Airlines
Sat, Sep 19 - Thu, Sep 24
American Airlines Logo
6:40 am - 6:40 pm
SEA
-
BOS
9h 00m
1 stop
American Airlines Logo
2:58 pm - 9:36 pm
BOS
-
SEA
9h 38m
1 stop
$317American Airlines
Tue, Sep 15 - Tue, Sep 22
Southwest Logo
11:05 pm - 12:15 pm
SEA
-
BOS
10h 10m
1 stop
Southwest Logo
2:10 pm - 8:30 pm
BOS
-
SEA
9h 20m
1 stop
$317Southwest
Sat, Oct 24 - Tue, Nov 3
Southwest Logo
12:40 pm - 11:15 pm
SEA
-
BOS
7h 35m
1 stop
Southwest Logo
4:40 pm - 10:30 pm
BOS
-
SEA
8h 50m
1 stop
$317Southwest
Tue, Oct 6 - Wed, Oct 14
Multiple Airlines Logo
2:59 pm - 5:21 am
SEA
-
BOS
11h 22m
1 stop
Multiple Airlines Logo
6:59 pm - 10:38 pm
BOS
-
SEA
6h 39mnonstop
$322Multiple Airlines
Sat, Sep 19 - Wed, Sep 23
Multiple Airlines Logo
6:51 pm - 6:09 am
SEA
-
BOS
8h 18m
1 stop
Multiple Airlines Logo
7:20 pm - 10:37 pm
BOS
-
SEA
6h 17mnonstop
$322Multiple Airlines
Useful Info

Good to know

Low season

January

Cheapest flight

$184
Best time to beat the crowds with an average 4% drop in price.
Most popular time to fly with an average 28% 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

Flights from Seattle to Portsmouth: the best tips from KAYAK users' own experiences

Insights shared by verified travelers who flew the route from Seattle to Portsmouth 
rsmrostovFlew with Alaska Airlines
SEA
-
BOS
Jan 2026
If you have a small personal bag and a personal item you will be hustled to consolidate snacks on the flight of very poor so bring your own food and if you have an Android phone you likely will have issues connecting to Wi-Fi on the plane especially if the connection was dropped in the middle of watching a movie and then you attempt to reinstate it sometimes you have to clear browsing history and cookies becomes painful
Verified travelerFlew with Alaska Airlines
SEA
-
BOS
Jul 2024
Generally Alaska Airlines have very friendly and helpful people in my experience. They don’t have TVs in all planes so make sure to download their app if you want entertainment on the plane.

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 18m.

  • How many flights are there between Seattle and Portsmouth?

    42 direct flights run between Seattle and Portsmouth on a daily basis. On average, there are about 298 departures each week.

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

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

  • 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 5 days, the cheapest one-way ticket between Seattle and Portsmouth found on KAYAK was with American Airlines for $98. Hawaiian Airlines offered a round-trip connection from $118 and JetBlue from $153.

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 84 days before departure, on average.
  • Book at least 2 weeks before departure in order to get a below-average price.
  • High season is considered to be November, December and January. The cheapest month to fly is September.

Reviews of the 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.
7.9
Alaska AirlinesOverall score based on 12748 reviews
8.1Boarding
7.0Food
7.8Comfort
7.0Entertainment
8.5Crew
Airline reviews

I was offered a selection of drinks and given a free snack. The flight was only a couple of hours, but we were trreated better than the transatlantic flight.

10.0 ExcellentDiana, Aug 2026
SEA - SFO
Read more Alaska Airlines reviews

I was offered a selection of drinks and given a free snack. The flight was only a couple of hours, but we were trreated better than the transatlantic flight.

I was much more comfortable on this flight since it was not completely full. Again the complimentary food was inadequate for such a long flight. A tiny bag of mustard flavored pretzels and small drink . I'm glad I brought a few granola bars with me this time.

Plane was clean and modern and spacious, usb ports all worked. No TVs

Baggage pickup in Seattle took over an hour. We were told one, then moved to another, and then back to the original. What should have taken 15 minutes took over an hour. When waiting to board our flight in Seattle to return to DC, we were sent to 4 different gates before finding the right gate. I have walked every inch of Sea-Tac Airport. The actual flights were great. The rest, not so good. "Ain't no way to run a railroad."

Multi gate changes and flight delay were irritating. Food on board was terrible and expensive for what was offered.

Overall the experience was good. Check in at the bag drop was challenging as the system was having issues and there was only one attendant helping the passengers. My personal experience was okay as it was straight forward but there were many who were having issues. The flight was good. I did not use the in flight entertainment very much as I had brought my own but it seemed to work well.

Technically this was the flight where they lost my bags, but I already explained that on the review for my connecting flight, so I'm not gonna do it again.

Hate the way they nickel and dime you on pricing. Extra for baggage, extra for a pre assigned seat. Make it one price and be done with it.

Delayed due aircraft maintenance. The plane was so small, hardly to get to the toilet when they’re serving food/drinks. But the ground crews were so helpful and trying their best to update all situation. The flight attendants not as friendly but fine.

same as the first when you pay for choice of seats than you don't receive them its very frustrating it was an extra fee of $80 dollars Craig Molan

Comfortable seats. Nice service online. Short flight, so not a lot of time to enjoy.

The flight was done by SkyWest only WIFI no entertainment center are available on the CRJ

My flight was delayed by 4 hours in 30 minute increments. The gate agents were amazing but the communication was not. We were told that there was a maintenance issue but they didn't know what it was. That didn't inspire confidence. Then they said they found it and it was fixed and the pilot just needed to sign off. Then the pilot needed to talk to the other pilot from the arriving flight and we'd be fine. Then we were waiting for the pilot to call back. Then the maintenance issue wasn't fixed. Then they decided we were getting a new plane (why didn't they decide this earlier??). Fine. But then they announced we were changing gates AND terminals. And we were boarding in 20 minutes. So we all had to run to the new terminal gate. We could have taken off at that time, but we then had to wait for all the people who rebooked on a different flight to book this flight again. That took 30+ minutes because there was only one gate agent. When everyone ditched this flight, I saw it as an opportunity to upgrade to comfort. Delta, the greedy jerks they are, charged me $121. After their delay, their fault, their issues, couldn't even discount an upgrade. They only handed out $12 meal vouchers for the delay. I can't even get a snack from starbucks for that.

Love me some Delta. One of the few airlines to recognize and support veterans. Easy boarding, flight was on time and arrived early and the flight attendants were excellent on this flight.

We sat on the runway for over an hour before departure. That was unwelcome.

Crew was nice, meal was good. Entertainment had to be rebooted 3 times and still did not work. Turns out there was residue on screen, it needed to be cleaned to prevent the touchscreen buttons from continuously activating. I had entertainment for the last 45 minutes of a 5 hour 45 minute flight. Really unacceptable for first class. Flight attendent indicated your cleaning solution creates this problem. Seems as if this is widely known, you should be using a different product or cleaning better. Really really disappointing which simply added to the wi fi on your planes with reliably never ever works.

Snacks and included beverages were appreciated. Boarding went smoothly. Plenty of overhead bin space. Seats get very uncomfortable after a couple of hours. After waiting 10 painful minutes for my walker, a very nice Delta guest agent pushed me in a wheelchair to the gate. It was finally delivered to me after another 15 minutes . Our checked bag was on the carousel long b4 I was able to retrieve it. Fortunately it was still there but somewhere along the way the straps we used to secure it were removed and and were not reattached. Wish I had made note of the agents name.

The cabin temperature was nice and cool. The wifi was not working.

Could not get my connecting flight boarding pass until four hrs before departure! Ver annoying especially since the staff could not explain why!

First flight out and was 85 minutes delayed. Notification came out way too late

Flight be on time would be a good start. Then train your flight attendants to be attentive and friendly. This time they completely forgot my row for the measly snack! United, do better!

Our flight was delayed several Times due to mechanical issues. Although I understand this may happen at times, it was very inconvenient and we had to book a hotel for an overnight stay. We were traveling with my 3-yo grandson and waiting at the airport from noon until 6:30pm with no reassurance that our next rescheduled flight would depart, we had to decide what’s best for him. A day later, I found out that I may be able to demand compensation if my flight is delayed more than 4 hours. I will hav to read the fine print next time.

United needs to step up their game. Delayed flight leaving Seattle, San Francisco. Older aircraft, not very comfortable.

Had to cancel first flight because Airporter Bus took over 3 hrs to get to airport which resulted in an extra $378 dollar fare . Is there anyway I can be reimbursed for initial fare since it was not my fault? Sent from my iPhone EJ Ledet

Delayed by 2.5hrs any longer and they would’ve had to honour their own policy for breaking their own rules and regs. Not cool, especially when I have an infant child that needs to stay on a routine and they get schedules.

They had three choices for snacks - but you could only have one - and they ran out of the dark chocolate before they made it all the way down the aisle... Packed flight - limited service.

They opened my checked bag and even though my lock was tsa approved, they loose my lock and left my bag just like that. Incompetent people, very upset about it. I’ll try to avoid traveling with united

We fly to Ecuador frequently. Checking in is usually a hassle because most United agents take some time before they can verify that my passport doesn't require a visa to Ecuador. This time the process was even longer due to the cyber attack. But she was really nice to us. So glad we brought plenty of snacks to supplement the 3 flights from SEA to GYE.

We had selected seats in the app that were a 2x2 format in the middle of the plane. Our seats when we got on the plane had been moved to the back rows in a 3x1 format. What’s the point of paying up for tickets that allow seat selection if the airline will just change them?

The new Airbus A231neo has neat tech but the economy seats are so tight together that I always had my shoulders against one passenger or the other. I was very miffed that Basic Economy REQUIRES check-in of bags other than your personal carry-on; if you want to offer low-cost airline prices and then add services for a fee, just let me carry on my duffel. Hell, I could have put my carry on IN the duffel and called it a day but the gate agent would not let me; I ended up paying $40 for the risk of losing my bag. Not the worst flight, but far from the best.

Flight attendants and crew were great! This plane was fine. It was clean and everything worked properly. Now, the gate change was not communicated. No text or information. It wasn't far with the gate change but it still changed without any communication. Not sure if this is on American or Kayakl. Also, internet was the worst. I would never have ATT. 3+hr flight and weak internet. I think I watched the commercials to get on at least 6 times. Terrible internet!

So excited very proud first of all I wanna thank kayak all updates very professional and fast alart And amazing cabin crew so nice to me they deserve big salute

Great flight - friendly and attentive team! Seats in coach were comfy, but a little cramped - but that is the case with all airlines ;)

Dreadful experience. Our flight was delayed more than 8 hours due to a maintenance issue and the assistance from rebooking was poor. I was travelling with a bad knee and needed assistance waited in one place more than 3 hours before someone came with a wheelchair. The woman next to me was a 91 year old great grandmother who had waited more than 4 hours. There were moments of support from the staff but it appeared as they were going against the direction of management. It was apathy, lack of ownership and dismissive responses with small moments of kindness and understanding typically from grey haired, female, veteran staff..

Everything was great except it became so hot on the plane I couldn’t sleep on my red eye flight. It didn’t really cool down till we started descending.

The only thing is if Wi-Fi is available after you land and taxi to the gate. It takes forever to get to the gate, and having the Wi-Fi continue would be great to bide the time at least 5 minutes before you arrive at the entrance. That is my only comment; otherwise, everything was good.

Airplane was cold. Flight attendants were rude. Phone charger did not work. No food available.

Experience was fine. Seats were cramped, and we had to wait for repairs before we could take of. Even though the door remained open, we were warned that leaving the plane could cause difficulty trying to fly out later. Staff was pleasant, and climate control was fortunately working. We had trouble at the DFW terminal, but I don't think that was AA's fault.

This flight was fine but had no time to breathe as the connection was late from Sea to ORD.. Super stressful. If we checked bags, the trip would have been very distressed.

Boarding, Seating, Flight Attendants, flight was okay. My seat was uncomfortable.

A more comfortable seat. Padding would be really helpful but I've read the airlines don't want customers to be satisfied with economy seats.

Everything was good except checking bags . I had paid for two bags but it didn’t show so we had to do it again while people waited and we were struggling to get to our flight

Flight delayed 4 times on a non-stop from BOS to SFO. Then when landed in SFO had to wait for 30 mins for a gate AT 3:30AM.

Plane was delayed multiple times. I would like to request a refund. Was due to arrive Thursday evening ended up arriving Friday morning.

The seats were roomier than other airplanes I’ve been on.

The security line at JFK was one of the longest I’ve ever experienced - probably 45 minutes. I don’t know if JetBlue has control over it, but it detracted from the overall experience. Entertainment had good options, but the volume control was a bit small to tap on and the screen had a fair amount of interference blips. Clearer picture would have been better.

The flight was delayed for more than 3 hours the flight attendant was so angry, it was my first flight with JetBlue but i don’t think I flight with them again.

The plane was late to leave.. Internet was lousy. TV was not working. when we arrived, We stayed on the plane for a long time before we got to the gate. It took us a long time to retrieve our luggage because they didn’t know what carousel to send them to. It was a bad experience.

Seats were not too comfortable; it was impossible to locate the underseat power outlet.

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

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

Complete your trip to Portsmouth with a hotel stay or car rental