$127 Find Cheap Flights from San Francisco 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 San Francisco to Portsmouth departing on 2/18. 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
$226
Overall average: $461
United Airlines
Wed 12/10Fri 12/12
SFO - BOS • Non-stop
Cheapest non-stop
$227
Typical prices: $283-$526
Delta
Wed 12/3Fri 1/9
SFO - BOS • Non-stop
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Flight Deals
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Flight Deals

Cheap Flights from San Francisco to Portsmouth (SFO-BOS)

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

Wed, Dec 10 - Fri, Dec 12
United Airlines Logo
1:05 pm - 9:43 pmSFO-BOS
5h 38mnonstop
United Airlines Logo
6:00 am - 11:49 amBOS-SFO
8h 49m1 stop
$226United Airlines
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Wed, Dec 3 - Fri, Jan 9
Delta Logo
9:41 pm - 6:24 amSFO-BOS
5h 43mnonstop
Delta Logo
7:50 am - 11:50 amBOS-SFO
7h 00mnonstop
$227Delta
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Mon, Dec 22 - Wed, Jan 7
United Airlines Logo
11:25 pm - 8:10 amSFO-BOS
5h 45mnonstop
United Airlines Logo
7:55 am - 11:48 amBOS-SFO
6h 53mnonstop
$230United Airlines
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Sun, Dec 7 - Wed, Dec 10
United Airlines Logo
10:45 am - 7:24 pmSFO-BOS
5h 39mnonstop
United Airlines Logo
6:00 am - 9:45 amBOS-SFO
6h 45mnonstop
$231United Airlines
Find Deal
Fri, Dec 5 - Sat, Dec 6
Delta Logo
9:41 pm - 6:24 amSFO-BOS
5h 43mnonstop
Delta Logo
8:05 pm - 11:59 pmBOS-SFO
6h 54mnonstop
$232Delta
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Wed, Dec 3 - Tue, Jan 13
Multiple Airlines Logo
10:10 pm - 11:56 pmSFO-BOS
22h 46m2 stops
Multiple Airlines Logo
6:00 am - 1:24 pmBOS-SFO
10h 24m1 stop
$233Multiple Airlines
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Sun, Jan 11 - Sun, Jan 18
Frontier Logo
8:38 am - 1:19 amSFO-BOS
13h 41m2 stops
Frontier Logo
6:00 am - 1:24 pmBOS-SFO
10h 24m1 stop
$235Frontier
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Thu, Dec 11 - Tue, Dec 16
Southwest Logo
10:50 am - 9:40 pmSFO-BOS
7h 50m1 stop
Southwest Logo
7:20 am - 1:55 pmBOS-SFO
9h 35m1 stop
$236Southwest
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Fri, Dec 12 - Mon, Dec 15
Delta Logo
9:41 pm - 6:24 amSFO-BOS
5h 43mnonstop
Delta Logo
8:05 pm - 11:59 pmBOS-SFO
6h 54mnonstop
$237Delta
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Wed, Jan 7 - Wed, Jan 14
Multiple Airlines Logo
7:00 am - 5:39 pmSFO-BOS
7h 39m1 stop
Multiple Airlines Logo
6:00 am - 1:24 pmBOS-SFO
10h 24m1 stop
$238Multiple Airlines
Find Deal
Useful Info

Good to know

Low seasonJanuary
Cheapest flight$127
Best time to beat the crowds with an average 18% drop in price.
Most popular time to fly with an average 11% increase in price.
Flight from San Francisco to Boston

When to book flights from San Francisco to Portsmouth

Are your dates flexible? Find out the best times to travel from San Francisco 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 San Francisco to Portsmouth

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

    When flying out of San Francisco you’ll be using San Francisco. 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 San Francisco to Portsmouth take?

    Direct flights cover the 2,696 miles separating San Francisco and Portsmouth in about 5h 30m.

  • How many flights are there between San Francisco and Portsmouth?

    51 direct flights run between San Francisco and Portsmouth on a daily basis. On average, there are about 359 departures each week.

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

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

  • How does KAYAK find such low prices on flights from San Francisco 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 San Francisco to Portsmouth.

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

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to Portsmouth from San Francisco 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 San Francisco 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 San Francisco with another airline.

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

    In the last 72 hours, the cheapest one-way ticket between San Francisco and Portsmouth found on KAYAK was with Frontier for $127. United Airlines offered a round-trip connection from $226 and Delta from $227.

Top tips for finding cheap flights from San Francisco to Portsmouth

  • There is no airport in Portsmouth. Instead, you’ll be flying into Boston Logan Airport when flying between San Francisco and Portsmouth.
  • The cheapest flight from San Francisco to Portsmouth was found 69 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 January.

Reviews of the top 5 airlines serving San Francisco to Portsmouth

 
Need help choosing which airline to fly with from San Francisco 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 11326 reviews
7.8Comfort
8.5Crew
7.1Food
8.1Boarding
7.0Entertainment
Airline reviews

I love a red eye flight. No lines to wait in. Lots of turbulence on the flight and a very shaky landing.

8.0 ExcellentAnonymous, Nov 2025SFO - EWR
Read more Alaska Airlines reviews

I love a red eye flight. No lines to wait in. Lots of turbulence on the flight and a very shaky landing.

Flight was delayed 14 hours! We missed an entire day of our vacation and had to pay for hotel that we didn’t use

Could not check in online. Called airline twice, thinking Hawaiian Airlines could check me in during phone call. NO. In 2nd phone call, Customer Service explained that due to “transition period” of Hawaiian Airlines/Alaska Airlines merger, I could only check in at the airport. In addition, flight to Kahului was late at arrival gate; I made connection to Lihue but my bag did not, so I had to return to Lihue airport a couple hours after my arrival to retrieve the bag.

I still in San Francisco😡the flight has delay and lm not sure l can back to Seattle or not😡lm here from 7.30pm and still waiting😡 l never will use of Kayak.

On time boarding, take off and landing. Will fly again with Alaska Airlines.

Flight was smooth, pleasant passengers and crew. Enjoyed the experience

Flight attendant was awful, I felt second hand embarrassment with every one of her interactions with people onboard. She was so incredibly rude every chance she got

Great flight - efficient and cheerful team on board, at SFO gate. Also, PAE (Paine Field, Everett, WA) is a great little airport to fly out or in to!

I was sitting towards back of plane and the flight attendants I thought spoke unusually loud for an evening flight. They chatted and chatted all night long and it seemed odd to me that they didn’t try to lower their voices. It is annoying as a passenger to hear all their conversations.

Had to pay $8 for internet wasnt cool, no tv’s, had to use phone to watch movies, no food choices seemed available unless u ordered in advance maybe I'm wrong about that but seemed that way, no snacks were served. Seemed a very bare bones flight. But it was on time and safe so that was good

Our flight from SFO to MSP was right on time on 11/15/2025. No delays. As we approached MSP at about 8 pm, we circled in the air until 8:40 pm so I don't call that efficient for MSP. I think the captain should announce the delay and why. (as if we all don't know that we are just circling around the area, slowing down, speeding up, slowing down.) Thank you. Marilyn Fischer

Staff were friendly and happy. Delta could make sure passengers that don't have the app know of changes. Without Kayak I would not have known about the change of gate or the delay. Kayak was faster to notify me.

The flight used a B767 with a very old interior from before 2014. The entertainment system did not work at all during the flight despite attempts to reset the system. It was like they flew this route just to be competitive.

Delayed flight (1hour) plus a long layover after an overnight flight with no backup plane available.

Flight delayed for two and half hours and then canceled altogether due to mechanical issues. No mechanic onsite to fix so had to send one from LAX.

My husband upgraded our seats and I don't know if it was due to the type of planet was or if they didn't upgrade our seats. We were supposed to be in I believe comfort seats and they were just as tight as any other seat- no leg room and we are very tall people but at least it wasn't extremely cold. My husband did put in a complaint about our seating because he paid extra and if we would have known that the space and the tightness would have been the same, we just would have gotten the emergency row emergency row seats that we normally get. We love Delta but both our flights coming home we're not good. Oh I forgot to mention that on our flight to Hawaii our luggage wheels got broke and we had to purse new luggage on vacation then we never had this problem so we didn't know protocol and reported it after we got home only for them to tell is we only had 24hrs to report the damage. Not sure what was going on with Delta this vacation trip.

Crew was excellent. Comfort seats not as nice as other kinds of planes.

It was a great flight and the stewards and stewardess were all kind and accommodating!! The seats were comfortable and entertainment screen excellent!

There are 4 flights in consecutive gates with about the same departure time. Two flights were boarding at the same time. One was delayed or boarding would be happening at the same time. I am not sure what Delta and LAX need to do to have a better layout at the end of Terminal 2

There was a security issue at the airport and we were unable to land. We circled endlessly and then landed at another airfield for fuel. We then circled the airport again, almost landed but didn’t fully touch down before circling again. I am thankful to the crew for keeping us safe- the issue was the airline and staff at the airport getting us seats on our connecting flights. That part was hours of searching for someone and getting in double my steps.

I received several emails about my 3:10 flight. When I showed up to the airport at 12:30 to check my bags I was told the flight was actually at 1 pm. They grudgingly rebooked me for a flight at 5:22 to Vegas to get a connecting to LAX. I did find the gate for my original 3:10 flight but they were booked. I proceeded to receive status updates and gate change information for the 3:10 flight, even though I was apparently never supposed to be on that flight

The food options were limited and very specific. Some type of entertainment option for a 4.5 hour flight would have been nice.

The Kayak confirmation number did not work for checking in the day before. I checked in at 8.30 using my ticket number. When I arrived at the airport, I was informed that the flight was overbooked, and since I had checked in late, I did not have a seat. The Next flight was not until ten PM. I called my wife, who had been taking care of our kids all weekend, and she was upset, calling me a liar and telling me to stay in SD. It turned my weekend getaway into a nightmare! I blame the Kayak website and will not book flights using your app in the future.

comfortable but the food is horrible. I have flown Hawaiian several times now and no matter what they say the food is its the same squashed bread with melted goop inside. Tastes fake and isnt what they represent, its quite nasty. What happend to real food? And there is NO entertainment!! so not sure why they are asking for a review on that.

Good and friendly staff. Nicely enjoyed the complimentary drink and snack.

I was very, very cold and a stranger loaned me her sweater next to me. I didn’t wanna buy a blanket just for a four hour trip when I did not need the pillow or the earphones. I don’t mind purchasing a blanket, but I only needed that not all of it accessories. Cold air pretty much blew the entire trip. Two people in front of me both bought the blanket packages. Maybe that’s the idea. The crew was exceptionally nice and passed through multiple times.. the restrooms were very clean and usually accessible.

3 hour wait on customer service after flight was cancelled. Was bumped to a flight where I wouldnt have gotten to my destination for another 2 days. Had to fully refund flight and book a new one the following morning. Paid twice the amount for the flight than I had originally booked. Very disappointed I was not offered any sort of discount or points for all of the frustration, in fact the airline profited twice as much off of me by cancelling my flight and and changing my entire trip.

I understand that both Hawaiian and Alaskan are in the process of merging but I could not get real-time flight info or access my boarding pass on either app

Had a hard time checking into my flight on my phone because they gave me the wrong confirmation number. Otherwise everything else went well.

All was good and they were able to seat my travel companion next to me. Thank you.

This was an older airplane. The cabin was constantly warm to hot throughout the 10 hour flight and there were no vents to personalize air flow. Also since it was an older plane, the material and comfort of the chairs were very uncomfortable. I left my flight with major soreness on my tailbone.

Older aircraft, no meal, only food was for purchase. Not impressed United.

Not pleasant trip cross country when the entertainment and WiFi system not working. No entertainment for entirety of route. Staff was rather nonchalant in that they dismissed the problem due to age of plane. It would have been nice to know this up front so I could have come prepared to read or download movies before boarding Coincidentally or not, there was a similar issue with the entertainment system on my previous flight I took on my fist leg of the trip. There are no seat TVs, so you must rely on the app when it works. United can do better. Also, what use it it to pay for boarding group 2 when half of the passengers are in the same line as you?

My experience on this United Airlines flight was highly uncomfortable, primarily due to two issues: Cabin Temperature: The temperature on the Boeing 737 MAX 8 was unacceptably high, feeling consistently around 80 degrees throughout the flight. This made sleeping impossible and significantly detracted from the experience. Seating Arrangement: Being stuck in a middle seat for a six-and-a-half-hour overnight flight compounded the discomfort. Moving forward, I will always purchase a seat assignment to avoid this situation.

Premium Plus is a really good idea for longer flights

Same as last comment. Food sucks. Quality. Not surprising most people have no clue about nourishment Clearly

We were in business class. the angled seats in that class do not have a real window view & the placement of the controls are bad. But we knew that. But the food options were mediocre. The taste was fine, but the size was for a child. It’s just really feels like United is skimping on everything. Even when we were in the Polaris lounge they did not have diet sodas. They said they were out no Coke zero no Diet Coke, etc. I do not think the portion of nuts they serve on the plane could get any smaller. Really a minimal service and offer for what you’re paying for in business.

We had to deboard 2 times due to maintenance issues. They changed the plane, and then we got deviated to LAX due to maibtenance issues on the other plane, had to sleep at LAX and los a full day.

From the first moment you interact with United Airlines, you can expect nothing less but extreme frustration. The baggage handler at the bag drop seems completely unbothered by the presence of customers waiting in line. No help was extended to load the baggage whatsoever. And if any of your bags is overweight by 0.01 pound they will make you re-distribute everything in your suitcase just to play power trip. When it was time to board no help was extended to customers to locate their seats. Moreover. It was a chaotic mess at the gate when it was unclear who should board first and everyone just bunched up, trying to get on the plane. I am sure the crew was doing their best to perform their jobs while being paid their wages however it shouldn’t be that hard to smile once or twice when you’re in the business if serving customers. It is a shame for the United States of America to have a flagship carrier of such low caliber. Our flight was also delayed by about an hour and a half due to further delays prior to our inbound flight. Being someone who has travelled for both business and leisure in Asia, Europe, and South America I have never experienced such poor quality of service.

Stuck on tarmac for two hours plus a 5.5 hour flight. Rude flight attendant. And no meals, not even for purchase!

The flight was two hours late due to a computer fault and resulting maintenance. Nothing was offered as compensation beyond bottles of water during the time we were deplaned and waiting in the terminal.

Very pleasant flight attendants. Gate crew rather loud chatting with each other.

Four plus hour flight delay in New York caused us to take off after 11:30pm. We didn’t arrive at our hotel until five hours after check in. Started the trip off feeling exhausted.

Plane was in bad shape. TV’s and WiFi didn’t work. Plane need a refresh. Not enough room for bags.

Everything was great. I liked the text updates so that I never miss a gate change & I have all the latest info.

I don’t usually fly budget airlines or airlines in the United States. It was as good as any other airline. The seats are comfortable and the airline attendants are not rude & surly. Very nice flight (s).

They have the most inexperienced / rude flight staff I’ve encountered

very difficult boarding process - aggressive passengers not the friendliest crew

WiFi was not eorkig (again) And the plane was from 1990 with the screens which were.not touch and most didn’t even work and if lucky could tune in tv

I paid extra for a seat closer to the front. The TV didn’t work at all for the entire flight. Would have been nice to know before I purchased an “upgraded “ seat

Everything you need to know for your flight from San Francisco to Portsmouth

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