IAD - OPO

$287 Find Cheap Flights from Washington Dulles Airport to Porto

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from Dulles Intl to Porto departing on 5/13. 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 to Porto

 
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Washington, D.C. to Porto.
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Washington, D.C. to Porto.
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Everything you should know

Cheapest round-trip
$479
Overall average: $669
TAP AIR PORTUGAL
Sun 2/15Mon 3/2
IAD - OPO • 1 stop
Cheapest one-way
$287
Typical prices: $466-$700
SWISS
Wed 5/13
IAD - OPO • 1 stop
Top airlines
TAP AIR PORTUGAL
Cheapest • from $479 (round-trip)
Delta
Best reviews • 7.9 score
Airline reviews
Airline reviews
+1
+1
Airline reviews
Airline reviews
+1
When to book
3 weeks
in advance
Our data shows that travelers who book at least 3 weeks in advance save around 39% compared to booking last minute.
Insights
Insights
Insights
Insights
When to travel
October
Cheapest • 26% price drop
July
Most popular
Good to know
Good to know
+1
+1
Good to know
Good to know
+1
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 Porto!
Flight Deals
Booking Insights
Flight Deals

Cheap Flights from Dulles Intl to Porto (IAD-OPO)

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Dulles Intl to Porto 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 Dulles Intl to Porto

Sun, Feb 15 - Mon, Mar 2
TAP AIR PORTUGAL Logo
10:30 pm - 7:00 pm
IAD
-
OPO
15h 30m
1 stop
TAP AIR PORTUGAL Logo
8:00 pm - 2:35 pm
OPO
-
IAD
23h 35m
1 stop
$479TAP AIR PORTUGAL
Mon, Mar 9 - Mon, Mar 16
Multiple Airlines Logo
6:30 pm - 5:00 pm
IAD
-
OPO
18h 30m
2 stops
Multiple Airlines Logo
1:15 pm - 3:35 pm
OPO
-
IAD
30h 20m
2 stops
$490Multiple Airlines
Mon, Apr 13 - Wed, May 6
TAP AIR PORTUGAL Logo
10:35 pm - 5:00 pm
IAD
-
OPO
13h 25m
1 stop
TAP AIR PORTUGAL Logo
7:00 am - 3:05 pm
OPO
-
IAD
13h 05m
1 stop
$509TAP AIR PORTUGAL
Mon, Mar 9 - Mon, Mar 16
TAP AIR PORTUGAL Logo
6:30 pm - 3:00 pm
IAD
-
OPO
16h 30m
1 stop
TAP AIR PORTUGAL Logo
5:55 pm - 3:35 pm
OPO
-
IAD
25h 40m
1 stop
$514TAP AIR PORTUGAL
Sun, Apr 5 - Tue, Apr 21
TAP AIR PORTUGAL Logo
10:35 pm - 8:25 pm
IAD
-
OPO
16h 50m
1 stop
TAP AIR PORTUGAL Logo
9:00 am - 3:05 pm
OPO
-
IAD
11h 05m
1 stop
$521TAP AIR PORTUGAL
Mon, Apr 13 - Mon, Apr 20
TAP AIR PORTUGAL Logo
10:35 pm - 8:25 pm
IAD
-
OPO
16h 50m
1 stop
TAP AIR PORTUGAL Logo
7:00 am - 8:35 pm
OPO
-
IAD
18h 35m
1 stop
$529TAP AIR PORTUGAL
Tue, Apr 7 - Tue, Apr 14
Lufthansa Logo
5:55 pm - 11:10 am
IAD
-
OPO
12h 15m
1 stop
Lufthansa Logo
11:05 am - 7:25 pm
OPO
-
IAD
13h 20m
1 stop
$539Lufthansa
Mon, Mar 16 - Wed, Mar 25
TAP AIR PORTUGAL Logo
6:30 pm - 10:00 am
IAD
-
OPO
11h 30m
1 stop
TAP AIR PORTUGAL Logo
4:05 pm - 4:15 pm
OPO
-
IAD
28h 10m
1 stop
$542TAP AIR PORTUGAL
Thu, Apr 16 - Wed, Apr 22
Scandinavian Airlines Logo
8:20 pm - 8:40 am
IAD
-
OPO
31h 20m
1 stop
Scandinavian Airlines Logo
11:50 am - 4:50 pm
OPO
-
IAD
34h 00m
1 stop
$543Scandinavian Airlines
Tue, Apr 7 - Tue, Apr 14
SWISS Logo
8:20 pm - 7:55 am
IAD
-
OPO
30h 35m
1 stop
SWISS Logo
12:15 pm - 4:45 pm
OPO
-
IAD
33h 30m
1 stop
$547SWISS
Booking Insights

KAYAK's insights & trends for Dulles Intl to Porto flights

Get data-powered insights and trends into flights from Dulles Intl to Porto to help you find the cheapest flights, the best time to fly and much more.

What is the cheapest month to fly from Washington, D.C. Dulles Intl Airport to Porto?

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from Washington, D.C. Dulles Intl Airport to Porto, removes the top 0.1% to account for outliers, and then takes the median of all values for each month.

The cheapest month for flights from Washington, D.C. Dulles Intl Airport to Porto is October, where tickets cost $530 (return) on average. On the other hand, the most expensive months are December and May, where the average cost of round-trip tickets is $886 and $872 respectively.

How far in advance should I book a flight from Washington, D.C. Dulles Intl Airport to Porto?

To calculate weekly average prices, KAYAK takes all prices for each week before departure over the last year for round-trip flights from Washington, D.C. Dulles Intl Airport to Porto, removes the top 0.1% to account for outliers, and then takes the average of all the values for each week.

To get a below average price on the flight from Washington, D.C. Dulles Intl Airport to Porto, you should book around 3 weeks before departure, which saves you about 39% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 24 weeks before departure.

Good to know

Low seasonJanuary
Cheapest flight$287
Best time to beat the crowds with an average 15% drop in price.
Most popular time to fly with an average 15% increase in price.
Flight from Washington Dulles Airport to Porto

When to book flights from Dulles Intl to Porto

Are your dates flexible? Find out the best times to travel from Dulles Intl to Porto based on our flight data from the last year. Discover the cheapest month and even day to fly.
Estimated round-trip price
KAYAK looks at all historical flight data for each date to provide a predicted price for one-way trips or round-trips with a duration up to 40 days. While we try to provide actual minimum prices for each date, some prices are predictions and actual prices may differ.

FAQs for booking Washington Dulles Airport to Porto flights

  • How much luggage can I bring with me from Washington Dulles (IAD) to Porto (OPO)?

    The base fares on KLM, Delta, and TAP Air Portugal include one personal item and a carry-on free of charge. Any checked bags must be paid for separately. Another alternative would be to upgrade your ticket, which would increase your baggage allowance. The Standard fare with KLM includes one checked bag of up to 50 lbs. With Business class on American Airlines, you will have your carry-on and two checked bags included.

  • Can I fly with a service animal from Washington Dulles (IAD) to Porto (OPO)?

    On TAP Air Portugal, the dog must be a certified service animal (SVAN) with the appropriate paperwork and vaccination records. If they meet all the requirements, they are permitted to travel in the cabin, outside a carrier. You can request any special assistance services up to 48 hours before your trip.

  • Do I need a visa to fly to Porto?

    Portugal is a member of the EU, so American citizens and permanent residents do not need a visa to enter. Your stay in Portugal, or any other EU country, must not exceed 90 days and can only be for travel. You will be required to have a valid passport with at least 6 months of validity and at least one blank page for the stamps.

  • How do I get from Francisco Carneiro Airport (OPO) to the city center in Porto?

    If you are on a budget, then the metro is the most affordable way to get into the city. There is a station located directly at the airport and the trains run from 5 am to 1:15 am. It will take you around 30 minutes to reach the city center. Taxis are also readily available, the ride will cost around €20 to €30 ($22 to $33). For the most ease and comfort, you can book a private transfer from a service like Welcome Pickups.

  • What is the cheapest flight from Washington, D.C. Dulles Intl Airport to Porto?

    In the last 3 days, the lowest price for a flight from Washington, D.C. Dulles Intl Airport to Porto was $323 for a one-way ticket and $479 for a round-trip.

  • Do I need a passport to fly between Washington Dulles Airport and Porto?

    Yes

  • Which airports will I be using when flying from Washington Dulles Airport to Porto?

    Washington Dulles Airport and Porto are both served by 1 main airport. You will leave Washington Dulles Airport from Washington, D.C. Dulles Intl and will be arriving at Porto.

  • Which aircraft models fly most regularly from Washington Dulles Airport to Porto?

    We unfortunately don’t have that data for this specific route.

  • Which airline alliances offer flights from Washington Dulles Airport to Porto?

    oneworld, SkyTeam, and Star Alliance are the airline alliances operating flights between Washington Dulles Airport and Porto, with oneworld being the most commonly used for this route.

  • What is the most popular layover when flying to Porto from Washington Dulles Airport?

    Lisbon is the most popular layover city among KAYAK users traveling from Washington Dulles Airport to Porto.

  • Which is the best airline for flights from Washington, D.C. to Porto, Delta or KLM?

    The two airlines most popular with KAYAK users for flights from Washington, D.C. to Porto are Delta and KLM. With an average price for the route of $886 and an overall rating of 7.9, Delta is the most popular choice. KLM is also a great choice for the route, with an average price of $731 and an overall rating of 7.7.

  • How does KAYAK find such low prices on flights from Washington Dulles Airport to Porto?

    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 Washington Dulles Airport to Porto.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from Washington Dulles Airport to Porto?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to Porto from Washington Dulles Airport 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 Washington Dulles Airport to Porto?

    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 Porto with an airline and back to Washington Dulles Airport with another airline. Booking your flights between Washington Dulles Airport and OPO can sometimes prove cheaper using this method.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from Washington Dulles Airport to Porto?

    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 Porto from Washington Dulles Airport up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

KAYAK’s top tips for finding a cheap flight from Washington, D.C. Dulles Intl Airport to Porto

  • All flights along this route from Washington Dulles Airport (IAD) to Porto (OPO) will have at least one stop. Amsterdam (AMS), Madrid (MAD), Lisbon (LIS), and Paris (CDG) are the most common layover cities.
  • Flights on KLM along this route will often have a long layover in their hub city, Amsterdam (AMS). All passengers can access the two Crown Lounges for free. If you upgrade to Business class, lounge access will be included.
  • All airlines give a 24-hour window from the time of booking in which you can modify your flight for free. You can keep your travel plans flexible by upgrading to Standard fare on KLM – which allows ticket changes for free, or their Flex fare – which is refundable if you need to cancel.
  • With TAP Air Portugal, you might be able to get a deal on your upgrade with their auction feature. Up to 36 hours before your flight, you can bid the amount you’re willing to pay and will receive a confirmation if accepted.
  • KLM welcomes families on board by ensuring they are seated together and providing special entertainment for the kids. They offer activity packs and special kid's meals to keep your little ones happy during the flight.

Reviews of the top 5 airlines serving from Dulles Intl to Porto

 
See real verified KAYAK customer reviews for airlines flying from Washington, D.C. to Porto. Airline scores are aggregated from all reviews left by passengers on KAYAK after flying with an airline. KAYAK doesn’t show reviews that are older than 5 years. Learn how KAYAK collects reviews.
Need help choosing which airline to fly with from Dulles Intl to Porto? 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
DeltaOverall score based on 8178 reviews
8.1Boarding
7.2Food
7.8Entertainment
7.9Comfort
8.5Crew
Airline reviews

Was forced to check in my small carry on, even though I informed the crew it has very fragile items inside

2.0 MediocreJaspreet, Feb 2026
SEA - SMF
Read more Delta reviews

Was forced to check in my small carry on, even though I informed the crew it has very fragile items inside

This was one of the worst flights I’ve been on in years. I upgraded to comfort and had such an uncomfortable experience. The person next to me was oversized - which I understand - however, they took up their space and mine. I could only use about 50% of my seat space to not be physically touching this person the entire flight and there was no spatial awareness. I also could not use the seat outlet because their body was obstructing it. It was very inconvenient. Their body kept touching me repeatedly during the flight and I felt very uncomfortable. To pay more for an upgraded space and then not even being able to use it was highly disappointing.

No wheel chair as requested at Atlanta arrival on first flight.

Only freetext wifi was available in flight; browsing WiFi required payment. Since the seats had no in flight entertainment, Delta should revisit this policy on this longer flight.

Only water, tea or coffee served midflight, even to comfort seating. Man next to me needed two seats and took up a portion of my seat and Delta did nothing.

The flight was great as well as the airline staff

First class and monitors weren’t working for mine & my husbands. Eventually fixed, but quite annoyed as we bought first class. Also, No foot rests.

Prior to takeoff, the pilot told us there was a possibility of not being able to land and going to Portland. Well that happened, we took off and then did 8 loops around Spokane before the pilot told us we ran out of fuel and had to go to Portland. So for a 35 minute flight we have now been on the plane for 3 hours (boarded at 6:50 am and landed in Portland at 10:30). Then, we just sat in Portland's airport with no updates of when we can start heading back. All of a sudden, our pilots and crew just left, leaving us stranded in a different city and state. We continued to sit in Portland until we finally got a new crew assigned and boarded the plane (This was from 10:30-2). We then sat on the plane for an additional hour before take off because they had to count us multiple times. We finally landed in Spokane at 3:55 PM. So a flight that should have taken at max an hour took us 10 hours and we missed the majority of the recruiting event we went for.

It was delayed but other than that it was great.

Got on the plane and sat there for an hour before departure.

Wifi took a while to kick in and we had a maintenance issue that took over 40 mins at the gate in Washington before pulling back

Very good. Because of the delays with my previous flight, I missed my connection, but I was able to book another flight through the United app easily.

Was happy we finally got upgraded in 1st class. The seat getting old. The cushiness need some improvement.

Ineffective communication with United resulted in lost baggage. Their Baggage Tracing counter at MUC was shut down from 11:00-14:15 on my arrival. Undertrained, underinformed staff had me Running all over MUC to find someone to help me to no avail. Staff was rude, unhelpful, and unable to effectively use the systems they did have operational. They refused to contact United in any way or provide any accommodation or other resources while I waited for my luggage. This has destroyed my downstream itinerary. If they had even the slightest visibility I may have been able to reschedule/plan, but again, their staff provided nothing, and did nothing more than their website, which doesn’t even work on a standard phone browser. Miserable failure at all levels that weren’t associated with the operation of the aircraft.

Sat next to a one year old. She crawled all over the place and made me laugh.

The Crew and the food was the worst I ever had in Business Class. First they told us there were no space for carry on. It was plenty of space over our 2 row seats, we had to ask to let us travel with it which was accepted. They were aware that we had to run for the connection due to the previous flight delay. Have us one hour waiting for more customers and not even offer a glass of water. Then started the service and they started to serve other passengers drinks in business and did not offer any drinks until they serve our pre ordered meal and I ask for something to drink. I had to wait until they finished to serve all passengers until Inget something. The crew was the worts I ever had for Business Class in my life.

Not great experience - we were super late boarding due to issues with aircraft. Then when we finally all got onboard and seated and they started taxiing out to the runway they just stopped then turned around and went back to the airport. Apparently the crew “ran out of time” to legally fly us. They mentioned that they were about 2 minutes away from taking off. I understand the rules and safety but kinda wonder why they would have bothered boarding us in the first place? Had to go all the way back and de plane and then wait in a HUGE line to get a hotel (this is somewhere around 2:30am) finally got to hotel by Uber (no shuttle after 20min so gave up) and they ended up putting us all back on the same aircraft at 10am next morning so got about 2.5 hours sleep. They did give us. $250 credit, but it was a São Paulo Brazil flight out of Dulles. The flight and everything was fine.

Starlink wifi on the Embraer E175 is an excellent experience. I was able to connect and work from IAD all the way to approach into BTV.

7 hours delayed due to operational issues on United’s end. Basically laziness.

Short flight but an "eager to help" crew made the journey more enjoyable!

We upgraded to business class. Nice seat with lots of room but otherwise not impressive.

Delayed departure Madrid to Lisboa and my luggage no arrived

this flight was awful from pre-boarding to on the plane. There needs to be more coordination between TAP and My Way. We were in first class and I am handicapped. BY the time we got on the plane there was no place for our baggage and the crew did not handle the situation well. They gave us an argument and said that we'd have to have it checked. Then, after I complained they moved some people's bags to put our small carry ons several seats back of our seats which were in Row 4.

Late. Lack of updates. Rude hostesses. Terrible food. Lack of headphones.

Flight was delayed but crew gave little to no communication, then “began boarding” but really just had everyone stand up and wait for an hour without any news or updates, as if we were going to start boarding at any second. Total chaos. Seemed like this was their first time boarding a plane. When we arrived at our destination, we waited for over an hour for the baggage claim belt to even turn on. Probably waited at baggage claim for our luggage for close to two hours. Everyone was very confused and of course we all worried that the luggage was lost. Again, zero communication and everyone we asked just said “I don’t know.” So we were left wondering whether to wait, or file a missing baggage claim, or check the other baggage claim belts (which we did every fifteen-twenty minutes because we were just confused). Lack of communication throughout the experience was a huge issue.

The value is there, but the layovers in Lisbon were not great. The passport control was so bad that a 2 hour layover became very tight and on the return the Terminal was barebones which made it a long 3 hours.

From Casablanca to Lisbon our baggage 2 pound over they want me to pay $120 for 2 pound which unexpected we are two family 8 of us they counters lady her customer service is not good I fly frequently for my business next time fly with TAP Air I will think twice

Booked business with TAP from LAX to Cabo Verde - overall ok, but just doesn’t feel like business class. More of a budget airline

Poor. Our flight was delayed and they told me I would be fine to make my connection in Lisbon, I missed it. Then they told me my bag would be automatically loaded onto my new flight to rome. It wasn’t. It’s been 4 days and I still don’t have it.

I like the price. I dislike the website where I wanted to ask questions about the unusual high prices of the luggage fees. I called the toll free number from the United States and I cannot get through. You should test your own toll free website for info and you will know what I am writing about.

Excellent lie flat seat for premium economy! Great staff. Bad food . Not so great entertainment. My bag didn’t make it either.

Really like the idea experience on this airline I will use again

Plane delayed due to weather. Plane boarded, then told to unboard due to a maintenance issue.

the seats were so cramped you could barely move. it was difficult to eat when passengers would recline their seats. the seats were so flimsy and unstable that whenever someone got in and out of their seat, it bounced like a spring back in your face. the movies were nice. the food was terrible. even though the conditions were terrible, they tried to pressure passengers to relocate their seats to accommodate adults who were related and wanted to sit next to each other, even after the passengers expressed that they did not want to move for that purpose. on the connecting flight, the “service” consisted of items for purchase. even though the flight was only 45 minutes, once again passengers (including me) were pressured to relocate for people to sit next to each other. they couldn’t be apart for 45 minutes? this was much less compelling than being apart for an 8 hour flight.

Everything went smoothly, and we even arrived 40min earlier than scheduled, on an Orland-Madrid route.

The staff was very nice and helpful. Some of the best crew I have met.

Suddenly, I don't find my flight back on the app Help Ticket 0757345716866 Hoeflich Flight back Sunday ib5333 Ib2629 Ib4268

Was all good.l including a sofdrink. AA improved significantly. There was no entertainment.

Flight cancelled, lost a day of travel where we were trying to meet friends we couldn't meet. Iberia website is very difficult to navigate and has lots of dead links. If you do not speak Spanish it is even harder. Tried communicating on their WhatsApp and that was also close to impossible. We were told we'd be compensated 150EU's for this cancelled flight but there is no avenue towards rectifying this issue. I've had to take it up with my credit card to contest the charges and not pay for a flight that didn't happen but doubt I will ever be reimbursed for my two Ubers to the airport where we never even departed or the 150EU's we were told we would receive. I would never fly Iberia again. Clown show.

The food on the flight was of marginal quality. Small bits of chicken, instant mashed potatoes and some carrots. The rolls were very dry, nearly inedible. The seats were quite small and didn’t allow for any shifting of position during the flight. There was limited leg room.0

Excellent service; they helped me reschedule so I can fly in an earlier flight

I had a good comfortable seat. There was nearly an hour delay. There was an accident with the champagne, but I was well compensated. These things happen sometimes.

Service and food were excellent. Incredibly friendly and competent staff. Flight was delayed over and hour and I had to run between terminals to get my connecting flight.

Missed it by a couple minutes and couldn’t find an alternative flight so had to spend the night in DC and after much shuffling from 1 airline to another managed to get a United to Frankfurt.

There were only 2 toilets and one of them did not work in business class. We are not allowed to cross classes so had to wait in line to use the toilets!! The entertainment touch display was finicky and did not work all the time.

We missed our flight. There was not enough time built into the layover to get through immigration, customs, bagclaim, bag rechecking, and the long trip to another terminal and gate. Kayak really screwed up. We took the bus up to Wisconsin and then were picked up in Brookfield by private car. It was lucky we didnt miss the last bus out.

I tried both on line and by calling the Customer Service line to arrange for a special meal as i have food intolerances. I was under the impression from your service representative that I was successful. I was not. I cannot eat spicy foods and get very ill if i eat bell peppers. I could not eat either menu choice and no special meal was actually ordered. ( your representative tried to order it for a flight that did not have meal service!!! - found this out later). Your wonderful cabin crew managed to put together a fruit, salad, roll and cheese tray for me so I had something to eat. WHY WOULD YOU SERVE SPICY FOOD, WITH NO MILDER OPTION,ON AN INTERNATIONAL FLIGHT???

Crew was professional and great, flight was clean. However food was pathetic. I ordered a Hindu meal assuming no meat but they served chicken. Need to be very specific- Hindu meal should be categorize as Vegetarian - no meat or egg. Or it should be specific that we are serving meat.

Late flight Delays Poor service Poor staff Worst airline ever

Ground staff and cabin crew were excellent. Flight was perfectly on time. Zero issues.

Everything you need to know for your flight from Dulles Intl to Porto

Information on your arrival and departure airports