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$338+ Cheap flights from Porto (OPO) to San Francisco (SFO)

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 5/21. Fares are subject to change and may not be available on all flights or dates of travel.
OPO — SFO
May 19 — May 261
Mon 5/19
Mon 5/26
1 adult, Economy
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Cheapflights Tip: The best prices from Porto to San Francisco are usually found in February or January, booked 44 days in advance, depart on a Wednesday or Thursday and return on a Thursday

Cheap flight deals from Porto to San Francisco

Discover tips and strategies to find the most affordable flight options for your journey from Porto (OPO) to San Francisco (SFO). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated May 14, 2025.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
2 stars

Round-trip from

$643
(Iberia)

One-way from

$338
(Kiwi.com)

Popular in

October

Cheapest in

February

Average price

$743
Provider with most accurate pricing for Porto-San Francisco flight deals.
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Provider most trusted by Cheapflights users for Porto-San Francisco flights.
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From Porto to San Francisco
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One-way flight from Porto to San Francisco
Search Deals
Highest demand for flights based on searches. 12% potential increase in price ($128 potential increase over avg. RT price).
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Cheapest flight prices on average. 7% potential price decrease ($62 potential savings vs. average RT price).
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Average for round-trip flights in May 2025
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Find flight deals from Porto to San Francisco

Cheapest flights from Porto to San Francisco
Explore the most affordable flight options available from Porto to San Francisco. Find the lowest fares from popular airlines and budget airlines, with prices last updated on May 14, 2025.

This Iberia deal was found by Cheapflights users on 5/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Iberia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 5/228:15 amOPO - SFO
1 stop15h 55mIberia
Thu 6/55:45 pmSFO - OPO
1 stop18h 10mIberia
Deal found 5/13$631
This Iberia deal was found by Cheapflights users on 5/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Iberia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 5/298:15 amOPO - SFO
1 stop15h 55mMultiple Airlines
Mon 6/27:20 pmSFO - OPO
1 stop16h 30mMultiple Airlines
Deal found 5/13$643
This American Airlines deal was found by Cheapflights users on 5/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 5/2212:20 pmOPO - SFO
2 stops30h 16mAmerican Airlines
Thu 6/55:25 amSFO - OPO
2 stops30h 30mAmerican Airlines
Deal found 5/14$673
This United Airlines deal was found by Cheapflights users on 5/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 6/512:10 pmOPO - SFO
1 stop31h 25mUnited Airlines
Fri 6/2010:45 pmSFO - OPO
1 stop24h 10mUnited Airlines
Deal found 5/14$699
This British Airways deal was found by Cheapflights users on 5/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure British Airways is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 5/228:15 amOPO - SFO
1 stop15h 55mBritish Airways
Thu 6/55:45 pmSFO - OPO
1 stop29h 50mBritish Airways
Deal found 5/14$700
This Delta deal was found by Cheapflights users on 5/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 5/226:30 amOPO - SFO
2 stops21h 45mDelta
Thu 6/510:00 amSFO - OPO
2 stops21h 30mDelta
Deal found 5/13$712
This Flighttix deal was found by Cheapflights users on 5/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Flighttix is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 6/2812:35 pmOPO - SFO
1 stop15h 55mBrussels Airlines
Sun 7/66:00 amSFO - OPO
1 stop19h 45mBrussels Airlines
Deal found 5/13$812
This Gotogate deal was found by Cheapflights users on 5/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Gotogate is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 6/512:10 pmOPO - SFO
2 stops17h 52mAir Canada
Fri 6/2012:15 pmSFO - OPO
2 stops19h 30mAir Canada
Deal found 5/14$887
This Gurufare deal was found by Cheapflights users on 5/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Gurufare is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 6/1112:05 pmOPO - SFO
1 stop15h 45mLufthansa
Wed 6/181:20 pmSFO - OPO
1 stop25h 25mLufthansa
Deal found 5/14$963

Cheapflights Fare Finder

Customize your flight search to find flights from Porto to San Francisco that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated May 14, 2025.
Use the filters below to find and compare flights from Porto to San Francisco that are best for you.

Fly from

Porto

Fly to

San Francisco

Route

Depart

Return

Price

PortoSan Francisco

OPO - SFO

OPOSFO

Porto

Thu 5/29

8:15 am-4:10 pm

1 stop15h 55m

San Francisco

Mon 6/2

7:20 pm-7:50 pm

1 stop16h 30m

$643

PortoSan Francisco

OPO - SFO

OPOSFO

Porto

Thu 6/5

12:10 pm-11:35 am

1 stop31h 25m

San Francisco

Fri 6/20

10:45 pm-6:55 am

1 stop24h 10m

$699

PortoSan Francisco

OPO - SFO

OPOSFO

Porto

Wed 6/25

8:35 pm-4:10 pm

1 stop27h 35m

San Francisco

Tue 7/1

2:40 pm-7:55 pm

2 stops21h 15m

$767

PortoSan Francisco

OPO - SFO

OPOSFO

Porto

Wed 6/25

8:15 am-8:58 pm

2 stops20h 43m

San Francisco

Tue 7/1

2:40 pm-3:55 pm

2 stops17h 15m

$791

PortoSan Francisco

OPO - SFO

OPOSFO

Porto

Sat 6/28

12:35 pm-8:30 pm

1 stop15h 55m

San Francisco

Sun 7/6

6:00 am-9:45 am

1 stop19h 45m

$812

PortoSan Francisco

OPO - SFO

OPOSFO

Porto

Wed 6/25

6:15 am-12:23 am

2 stops26h 08m

San Francisco

Tue 7/1

10:55 am-3:30 pm

2 stops20h 35m

$821

PortoSan Francisco

OPO - SFO

OPOSFO

Porto

Thu 6/5

12:10 pm-10:02 pm

2 stops17h 52m

San Francisco

Fri 6/20

12:15 pm-3:45 pm

2 stops19h 30m

$887

PortoSan Francisco

OPO - SFO

OPOSFO

Porto

Wed 6/11

12:05 pm-7:50 pm

1 stop15h 45m

San Francisco

Wed 6/18

1:20 pm-10:45 pm

1 stop25h 25m

$963

PortoSan Francisco

OPO - SFO

OPOSFO

Porto

Fri 6/13

9:10 pm-1:50 pm

1 stop24h 40m

San Francisco

Tue 6/24

7:20 pm-7:30 pm

1 stop16h 10m

$2,498

PortoSan Francisco

OPO - SFO

OPOSFO

Porto

Wed 5/21

7:40 am-7:50 pm

2 stops44h 10m

$338

Flights are sorted by cheapest round-trip flights first.

Deals found on 5/13

Showing 1-10 of 22 results
1
2
3
  • Most accurate provider: When it comes to deals on Porto-San Francisco flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Porto-San Francisco flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Porto-San Francisco flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on Porto-San Francisco flights, Cheapflights users trust FlightHub the most. FlightHub has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for Porto-San Francisco flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

Best time to book a flight from Porto to San Francisco

Have a flexible travel schedule? Discover the best time to fly to San Francisco from Porto with our price prediction graph.
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Cheapflights Insights

Everything you need to know about your flight from Porto to San Francisco

How far ahead should I book a flight from Porto to San Francisco?

Use this chart to determine the optimal time to book a round-trip flight from Porto to San Francisco. Price data was last updated on May 9, 2025.

The price you pay for your flight from Porto to San Francisco may vary depending on when you book. For the best chance of a lower fare, look to book 44 days in advance of your trip. Fares are likely to increase a fortnight or so before your departure date.

What is the cheapest month to book a flight from Porto to San Francisco?

Currently, January is the cheapest month in which you can book a flight from Porto to San Francisco (average of $276). Flying from Porto to San Francisco in June is currently the most expensive (average of $378). 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.

What is the cheapest time of day to fly from OPO to SFO?

Find hourly flight availability from Porto to San Francisco. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated May 14, 2025.

When flying from Porto to San Francisco, the time of day you decide to fly out makes little to no difference towards the overall price you’ll pay on tickets.

Rainfall in San Francisco by month

Plan your trip to San Francisco by taking into account the average rainfall totals by month.

In terms of precipitation, rainfall in San Francisco ranges from 0.0 - 4.4 inches per month. January is typically the wettest month, when rainfall can reach 4.4 in. July is typically the driest time to visit San Francisco when rainfall is around 0.0 in.

Temperature in San Francisco by month

Plan your trip to San Francisco by taking into account the average temperature totals by month.

If weather is an important factor for your trip to San Francisco, use this chart to help with planning. For those seeking warmer temperatures, September is the ideal time of year to visit, when temperatures reach an average of 62.6 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 51.8 F).

Reviews of airlines servicing San Francisco

Get insights into the airlines that provide service to San Francisco. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to San Francisco. Reviews last updated May 14, 2025.
To help decide which airline to fly from Porto to San Francisco, see what other customers have to say about Delta, KLM and Air Transat. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
Delta
8.0
Very good
7,946 reviews

Boarding

8.2

Crew

8.5

Entertainment

7.9

Comfort

7.9

Food

7.3

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

TUS - LAX

Delta has consistently been the best U.S. airline for my travels and this flight was no exception
Delta
8.0
Very good
7,946 reviews
Delta
8.0
Very good
7,946 reviews

Boarding

8.2

Crew

8.5

Entertainment

7.9

Comfort

7.9

Food

7.3

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

TUS - LAX

Delta has consistently been the best U.S. airline for my travels and this flight was no exception
KLM
7.8
Good
1,343 reviews
Delta
8.0
Very good
7,946 reviews

Boarding

8.2

Crew

8.5

Entertainment

7.9

Comfort

7.9

Food

7.3

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

TUS - LAX

Delta has consistently been the best U.S. airline for my travels and this flight was no exception
Air Transat
7.8
Good
387 reviews
Delta
8.0
Very good
7,946 reviews

Boarding

8.2

Crew

8.5

Entertainment

7.9

Comfort

7.9

Food

7.3

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

TUS - LAX

Delta has consistently been the best U.S. airline for my travels and this flight was no exception
SWISS
7.5
Good
1,595 reviews
Delta
8.0
Very good
7,946 reviews

Boarding

8.2

Crew

8.5

Entertainment

7.9

Comfort

7.9

Food

7.3

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

TUS - LAX

Delta has consistently been the best U.S. airline for my travels and this flight was no exception
United Airlines
7.4
Good
8,730 reviews
Delta
8.0
Very good
7,946 reviews

Boarding

8.2

Crew

8.5

Entertainment

7.9

Comfort

7.9

Food

7.3

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

TUS - LAX

Delta has consistently been the best U.S. airline for my travels and this flight was no exception

Related info for your journey

Find useful and relevant information for your journey from Porto to San Francisco. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • What are the cheapest airlines flying from Porto to San Francisco round-trip?

    Our cheapest airline available from Porto to San Francisco is United Airlines. Our recent data shows that you can find tickets from as low as $699 on this airline. Additional options worth looking into are Iberia and American Airlines, starting at $767 and $791 round-trip. These flights start at 19% lower than the current average price 3 months from now.

  • What are the cheapest airlines to fly from Porto to San Francisco one-way?

    The cheapest airlines for a one-way flight from Porto to San Francisco are Iberia ($375), Vueling ($381), and TAP AIR PORTUGAL ($515).

  • Can I find deals for flights from Porto to San Francisco that include hotel bookings?

    Yes. In addition to deals on Porto to San Francisco flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Porto to San Francisco?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Porto to San Francisco.

  • Can I find deals for business class flights from Porto to San Francisco?

    Yes. Cheapflights offers flight deals from Porto to San Francisco by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from Porto to San Francisco?

    Currently, January is the cheapest month in which you can book a flight from Porto to San Francisco (average of $276). Flying from Porto to San Francisco in June is currently the most expensive (average of $378). 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.

See more FAQs

Traveling to a place near Porto?

Book flights to Porto if you plan to visit one of these locations
Roseville
Mountain View
Santa Cruz
Livermore
South San Francisco
Turlock
Watsonville
Manteca
Fairfield
Newark
Richmond
Hollister
Milpitas
Antioch
Hayward
Alameda
Sunnyvale
Daly City
Campbell
Union City

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Top 2 airlines flying from Porto to San Francisco

Discover the top 2 airlines that operate flights from Porto to San Francisco. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated May 14, 2025.
AirlineCheapestAverageFlexibilityOn-time
United AirlinesCheapest$657Average$873FlexibilityNo cancel feeOn-time69%
LufthansaCheapest$665Average$898FlexibilityNo cancel feeOn-time76%

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