$168 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 8/31. 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

KAYAK searches hundreds of travel sites at once for deals on flights from Seattle to Portsmouth

Travelers love KAYAK
41,299,237 searches in the past 7 days on KAYAK

Save 21% or moreCompare multiple travel sites with one search.

Track pricesNot ready to book? Create a price alert for when prices drop.

Free to useThere are no hidden charges or fees.

Filter your dealsChoose cabin class, free Wi-Fi and more.

Everything you should know

Cheapest round-trip
$316
Typical prices: $405-$237
JetBlue
Sun 9/20Mon 9/28
SEA - BOS • Non-stop
Cheapest non-stop
$316
Typical prices: $349-$523
JetBlue
Mon 7/13Tue 7/21
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.
FAQs
FAQs
FAQs
FAQs
Start a new search
KAYAK searches 100s of sites at once to find you the best travel deals.
We hope you love your trip to Portsmouth!
Flight Deals
Useful Info
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

Sun, Sep 20 - Mon, Sep 28
JetBlue Logo
11:55 pm - 8:19 am
SEA
-
BOS
5h 24mnonstop
JetBlue Logo
1:00 pm - 8:42 pm
BOS
-
SEA
10h 42m
1 stop
$316JetBlue
Wed, Aug 26 - Wed, Sep 9
Delta Logo
11:13 pm - 7:35 am
SEA
-
BOS
5h 22mnonstop
Delta Logo
7:45 am - 11:05 am
BOS
-
SEA
6h 20mnonstop
$317Delta
Wed, Sep 16 - Sun, Sep 20
Multiple Airlines Logo
11:06 pm - 7:39 am
SEA
-
BOS
5h 33mnonstop
Multiple Airlines Logo
6:59 pm - 10:38 pm
BOS
-
SEA
6h 39mnonstop
$318Multiple Airlines
Sun, Sep 13 - Tue, Sep 15
JetBlue Logo
11:55 pm - 8:19 am
SEA
-
BOS
5h 24mnonstop
JetBlue Logo
1:00 pm - 8:42 pm
BOS
-
SEA
10h 42m
1 stop
$320JetBlue
Mon, Sep 14 - Thu, Sep 17
JetBlue Logo
9:40 pm - 10:46 am
SEA
-
BOS
10h 06m
1 stop
JetBlue Logo
6:59 pm - 10:38 pm
BOS
-
SEA
6h 39mnonstop
$321JetBlue
Wed, Sep 16 - Sat, Sep 19
Alaska Airlines Logo
6:51 pm - 6:09 am
SEA
-
BOS
8h 18m
1 stop
Alaska Airlines Logo
7:59 pm - 11:12 pm
BOS
-
SEA
6h 13mnonstop
$322Alaska Airlines
Wed, Aug 26 - Tue, Sep 1
JetBlue Logo
11:44 pm - 8:00 am
SEA
-
BOS
5h 16mnonstop
JetBlue Logo
12:42 pm - 9:04 pm
BOS
-
SEA
11h 22m
1 stop
$325JetBlue
Fri, Oct 9 - Tue, Oct 13
JetBlue Logo
10:15 pm - 10:46 am
SEA
-
BOS
9h 31m
1 stop
JetBlue Logo
6:59 pm - 10:38 pm
BOS
-
SEA
6h 39mnonstop
$326JetBlue
Tue, Aug 25 - Tue, Sep 1
JetBlue Logo
11:44 pm - 8:00 am
SEA
-
BOS
5h 16mnonstop
JetBlue Logo
12:42 pm - 9:04 pm
BOS
-
SEA
11h 22m
1 stop
$327JetBlue
Tue, Jul 14 - Tue, Jul 21
Multiple Airlines Logo
6:21 am - 5:40 am
SEA
-
BOS
20h 19m
1 stop
Multiple Airlines Logo
7:10 am - 10:33 am
BOS
-
SEA
6h 23mnonstop
$328Multiple Airlines
Useful Info

Good to know

Low seasonJanuary
Cheapest flight$168
Best time to beat the crowds with an average 2% drop in price.
Most popular time to fly and prices are also 22% lower on average.
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 14m.

  • How many flights are there between Seattle and Portsmouth?

    36 direct flights run between Seattle and Portsmouth on a daily basis. On average, there are about 254 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 $140.

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 70 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 12533 reviews
7.0Food
7.0Entertainment
8.1Boarding
8.5Crew
7.8Comfort
Airline reviews

On time, good seats, not overly full, up beast positive crew.

10.0 ExcellentAnonymous, Jun 2026
SEA - SBA
Read more Alaska Airlines reviews

On time, good seats, not overly full, up beast positive crew.

Airport security lines in Seattle were awful. The only staff that was pleasant and made the trip more enjoyable was the young woman at the gate in Seattle. She was so pleasant and helpful. Flight attendant on the plane seemed like she would rather be anywhere but on that plane.

People were friendly. Flight was a little delayed. Maybe I missed the reason for it. Overall a nice experience.

Crews were friendly enough. To help the airline I checked my carry on baggage. Typical "gonna be a full flight we need 19 carry on bags to be checked to help out". So I helped out only to have to wait 30+ mins for my luggage and risked not getting to my car rental on time. The return flight was delayed. Kept hearing employees say something about "they didn't have any power" which is kind of concerning. The air flow and air conditioning was insufficient. It was warm and stuffy during the flight. Plus no free wi-fi......Booooooo!

Didn’t even get on, check my flight to Seattle for details. Do better Alaska.

A five hour nonstop flight traveling over a few time zones and over the dinner hour and you get a small bag of pretzels. And no screens to watch movies. I

The flight kept getting delayed due to a maintenance issue. That happens, but there is no excuse for changing the gate FIVE TIMES, including one time nearly all the way across SeaTac. After we were delayed for 3+ hours, they did send us (via email) a $12 meal voucher...except you can't find a $12 meal anywhere in that airport, unless you consider a bag of M&M's and a bottle of water a meal. The plane had one problem after another but finally took off 4.5 hours late. This caused us to miss our hotel shuttle at ORD (they didn't run past midnight and it was 3 am) so we had to wait 25 minutes and pay for an Uber. I did get a $50 flight voucher from Alaska...big deal. Barely covers my Uber ride that I shouldn't have needed.

I upgraded to a better seat and it was much more comfortable. Nobody serves food anymore and actually on a 2+ hr flight not necessary. I didn’t even get water.

Check in & bag drop was straightforward. Alaskair changed the gate approx 40 min before departure, and I only became aware due to Google wallet update to my boarding pass. Had to move from gate N1 to C9 which required use of the Train, luckily I had time available.

Super impressed by staff courtesy, and assistance, Flight was one of the best I've had despite turbulence... Will definitely be flying Alaskan air as my preferred choice

Horrible. Faucet in sink not working, wifi not working. Didn’t bring food or snacks

Flight was delayed before take off and at landing. Baggage took 20 minutes. Flight crew would not serve full soft drink and had to ask multiple times before receiving water.

From checking to boarding, it was a seamless experience. The service agents were so helpful. The flight crew was so pleasant.

Gate agent showed up 20 minutes before boarding and was not at all friendly. Had to take this flight due to the one on the day before being cancelled and any later options were already full with long standby lists. Despite having paid for Delta Comfort seats, Delta did not allow me (or anyone) to choose their seat. The agent assigned them for everyone just prior to boarding. Self seat selection was allowed on the original flight. Flight staff was great - very friendly.

Flight attendants were great. Cheerful, upbeat and friendly. Jet, in particular, was fantastic.

I have Precheck. Flew HPN to DEN and return this past weekend. Delta didn't attach my Precheck number to this trip. So it was waiting in general line especially in Denver. Unavailable.

Original flight was delayed, then cancelled and the gate staff did not expedite rebooking. Also, no instructions were given that a ticket number was needed before being called to facilitate rebooking. This could have been much more organized.

Be on time? When not on time a circling for over an hour offer more than 1 bag of chips to the passengers? It was a 7 hour flight by the time we got done.

Five hour delays every hour, I wish it were all at once

Flight delayed four separate times. I’m now one hour hours late to landing.

Flight delayed two hours , missed connection flight then connection cancelled- horrible experience with hotel

Omg the disaster at the security was on another level! “Go to this end, sorry closed now, go to that end”. Ridiculous! This took over an hour! As far as the airline was concerned although I booked nearly a year ago I couldn’t get my bag tag - stand in another 15 minute line or my seat on Hawaiian Airlines- 5 more minutes! Then my TSA status was denied. Like what the heck! Makes a person not want to travel with this amount of incompetence

The Honolulu Hub needs 2 to 3 times the amount of things to do as well as shuttles that transport to/from gates and terminals. Arriving from OCONUS locations; transferring to CONUS locations its a miserable experience. Fetching and re-checking bags, then returning to a gate across the airport take longer than any other large airport. If youre confused by what I mean, the process goes like this: Disembark plane Walk a mile to the main terminal Walk half a mile to baggage claim Wait 40 minutes for baggage Walk a mile to re-check-in baggage Wait 20 minutes for checking in those bags Fo back through the wrong TSA line because the signage is poor Almost miss the connecting flight because your gate is across the airport.

The checking was disaster, the crew wasn't behave well. It took us two hours to check in, after that thr line at the TSA was long, we barely make the flight. Bad airline

Fabulous if you have a portable wheelchair. They can store it in the galley and you can just walk out with it. Really nice and the flat seats are just incredible, very nice. iPads for movies, also pretty nice,

The crew were exceptionally nice and accommodating. My wife was tired after the flight from Haneda, Tokyo. They let her sleep and served her dinner later after she woke up, before we landed in PDX.

No charging outlets worked. Other than collecting trash attendants didn’t come around. No one could hear flight attendants announcements during the flight. Seat pads were horrible. Sitting on a board for 5 hours. What happened to Hawaiian airlines comfort, hospitality, and extras? Our pilots did an excellent job trying to minimize turbulence and incredible job in landing in windy conditions.

There was no wifi available at any price -- the plane did not have wifi equipment. Movie choices were blah - hits from the past; nothing recent. The food was blah airplane food. They should have had Mai Tai drinks available as per the Hawaiian Airlines magazine, but they had none onboard.

I like that if they asked you to checked in a bag at the gate they give you priority to board

Horrible food and crew. Crew were laughing and talking loud while people were trying to sleep

Significant delays on my trip to Chicago and my trip back to NY

Terrible boarding and first class experience. Nice staff but overall disorganized, dirty plane.

Delayed by 5 hours and I had to wit in the airport for more than 6+ hours.

weather delay of almost 2 hours then we landed and our gate wasn't available so we waited another 30 min

Flight had mechanical issues and it was delayed 30 mins - some of us boarded and then had to deplane.

technology worked well and everything ran smoothly. The seats are quite cramped so please don't try to re-engineer the cabin to squeeze more bodies on board.

Delayed flight more than I hour. When boarding we spent some additional time on the plane before takeoff ....

Flight was delayed due to connecting passengers. Lack of snack options bad. Sitting in Aisle, last cart run pulled the cart directly into my knee. Rude awakening.

We sat on plane at gate delayed without communication as to why we were just sitting there

Agency very bad had to cancelled my booking too many changes in the flight changed my flight to 1 week

I tried to book a flight with Jet Blue. Your third party company hijacked my attempt with a website that looked like I was booking with Jet Blue. I realized it when I paid. I tried to cancel and was told by a man in India that there were no refunds. $735 stolen, Thanks Kayak!

It was inexplicably canceled and we are stuck in LA, haven't gotten home and it has been an inconvenience having lost work (on unpaid leave for my husband).

JetBlue worker, Blythe, was so amazing at the DCA counter. If it wasn’t for her, I’m not sure we would’ve made it through. Please thank her!

They lost my luggage and refuse to help. Terrible airline. I've never experienced worse customer service in my life. Pretty much just told me too bad that I lost all my luggage, not caring that I am stuck in Europe for 2 weeks with absolutely nothing.

You should have had Wifi to make it much enjoyable.

The flight out was delayed from 3:40pm to 5pm and again to 8pm. We boarded after 5pm, had to disembark because they could not get the Engine started, then we switched gates and got a new plane and did not board until after 8pm.

The flight was delayed after already taxiing from the gate due to a malfunction. After 3 hours we were told the flight was canceled. The next flight available was Sunday. My daughter and I stayed overnight in the airport due to this issue. I was given a $12 meal voucher. Unacceptable

Whole experience was poor. Delayed 2 hours. Lied about the delays. Was all jet blues fault and tried to blame on air traffic control. Sent out other let trips and wouldn't allow people to switch aircraft.

My bag was not loaded on my flight. it was not communicated to me until i was waiting for my bag at my destination. there was no confirmation of when my bag was arriving and no way to track it.

Nice plane, clean, wifi available and movies. All the flight attendants were courteous.

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

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