IAD - OPO

$255 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 10/11. 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

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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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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

Thu, Nov 6 - Mon, Nov 17
United Airlines Logo
5:33 pm - 9:30 amIAD-OPO
10h 57m1 stop
United Airlines Logo
12:35 pm - 8:57 pmOPO-IAD
13h 22m1 stop
$544United Airlines
Find Deal
Fri, Mar 6 - Wed, Mar 11
British Airways Logo
9:45 pm - 7:00 pmIAD-OPO
16h 15m1 stop
British Airways Logo
6:30 pm - 4:35 pmOPO-IAD
26h 05m1 stop
$547British Airways
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Wed, Nov 12 - Sun, Nov 16
United Airlines Logo
9:45 am - 3:25 pmIAD-OPO
24h 40m2 stops
United Airlines Logo
6:00 am - 8:57 pmOPO-IAD
19h 57m2 stops
$548United Airlines
Find Deal
Tue, Oct 7 - Tue, Nov 4
Delta Logo
6:30 pm - 3:30 pmIAD-OPO
16h 00m1 stop
Delta Logo
11:15 am - 4:05 pmOPO-IAD
33h 50m1 stop
$554Delta
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Tue, Oct 7 - Tue, Nov 4
Delta Logo
6:30 pm - 3:30 pmIAD-OPO
16h 00m1 stop
Delta Logo
11:10 am - 11:57 amOPO-IAD
29h 47m2 stops
$564Delta
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Tue, Oct 7 - Mon, Nov 3
KLM Logo
9:20 pm - 3:30 pmIAD-OPO
13h 10m1 stop
KLM Logo
11:25 am - 4:35 pmOPO-IAD
34h 10m1 stop
$566KLM
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Thu, Mar 12 - Tue, Mar 17
Lufthansa Logo
7:00 pm - 2:45 pmIAD-OPO
15h 45m1 stop
Lufthansa Logo
6:00 am - 9:09 pmOPO-IAD
19h 09m2 stops
$568Lufthansa
Find Deal
Tue, Mar 3 - Tue, Mar 10
TAP AIR PORTUGAL Logo
5:30 pm - 10:10 amIAD-OPO
11h 40m1 stop
TAP AIR PORTUGAL Logo
6:55 am - 3:35 pmOPO-IAD
12h 40m1 stop
$570TAP AIR PORTUGAL
Find Deal
Fri, Mar 6 - Sun, Mar 8
TAP AIR PORTUGAL Logo
10:30 pm - 5:00 pmIAD-OPO
13h 30m1 stop
TAP AIR PORTUGAL Logo
11:00 am - 10:00 pmOPO-IAD
15h 00m1 stop
$583TAP AIR PORTUGAL
Find Deal
Fri, Nov 7 - Sat, Nov 15
Lufthansa Logo
10:55 pm - 10:25 pmIAD-OPO
18h 30m2 stops
Lufthansa Logo
6:00 am - 3:50 pmOPO-IAD
14h 50m1 stop
$584Lufthansa
Find Deal

Everything you should know

Top airlines
United Airlines
Cheapest • from $544 (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 15% compared to booking last minute.
Insights
Insights
Insights
Insights
When to travel
October
Cheapest • 28% price drop
July
Most popular
Good to know
Good to know
+1
+1
Good to know
Good to know
+1
Cheapest round-trip
$544
Typical prices: $551-643
United Airlines
Thu 11/6Mon 11/17
IAD - OPO • 1 stop
Cheapest one-way
$255
Typical prices: $258-401
TAP AIR PORTUGAL
Sat 10/11
IAD - OPO • 1 stop
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We hope you love your trip to Porto!
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.

How much is a round-trip flight from Washington, D.C. Dulles Intl Airport to Porto?

What’s the cheapest day of the week to fly from Washington Dulles Airport to Porto?

The average price of all round-trip flights from Washington, D.C. Dulles Intl Airport to Porto clicked on KAYAK for each day over the last 12 months.

If your flying dates are flexible, you should consider flying to Porto on a Sunday, as we generally find the cheapest rates on that day for this route. On the other hand, Friday is the most expensive day to fly from Washington Dulles Airport to Porto. For your return ticket, we recommend flying on a Monday and avoiding Wednesdays for the best deals.

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 $990 and $873 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 15% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 5 weeks before departure.

Good to know

Low seasonFebruary
Cheapest flight$255
Best time to beat the crowds with an average 27% drop in price.
Most popular time to fly with an average 16% 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 $255 for a one-way ticket and $544 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?

    Star Alliance, SkyTeam, and oneworld are the airline alliances operating flights between Washington Dulles Airport and Porto, with Star Alliance 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 $825 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 7.8.

  • 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 7954 reviews
8.5Crew
7.3Food
8.2Boarding
7.9Entertainment
7.9Comfort
Airline reviews

Perfect flight both ways. On time, courteous staff, plane comfortable and cool. Best domestic flights I’ve had in awhile.

10.0 ExcellentAnonymous, Sep 2025CLT - BOS
Read more Delta reviews

Perfect flight both ways. On time, courteous staff, plane comfortable and cool. Best domestic flights I’ve had in awhile.

The food was terrible especially for a 15 hour international flight. The crew was unpleasant as well.

Really low quality food especially for an international flight. The crew also was surprisingly unpleasant except couple of ladies. I know we were not in first class but that’s no reason to treat customers as less.

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.

Quick check in. Everything went smooth. I don't know what can be done about airline food.

Crew was good. The reservation got mixed up and they didn't have my TSA number. I am also a Silver Medallion and wasn't able to use Sky Priority.

Delta made it easy, comfortable and timely. The crew was fantastic.

This route with Delta always has delays or is cancelled. Aircrafts seem smaller and older. I fly Delta quite a bit - haven’t had issues with the international flights. But this route has always been the troublesome one

Nothing special. The crew never went out of their way for anything.

Three seats in first class were broken and while they were able to still acommodate us it was looking very touch and go and they had others they could not acommodate

Over 1 Hr delay. No APU so no AC on ground. Plane was hot during boarding and then they closed the doors over 20 minutes before engine start so interior of plane was steamy hot and stuffy. Could have been helped by opening doors until ready to depart.

Ad experience - been flying many years with them but they are losing out to other carriers with their service and bagage / seating policy. My 2 12-yo kids were not placed with the parent. Absurdity.

Short flight so it was okay. Nice crew, all very pleasant and professional. We were near the back in row 27 so just as we got our drinks, we started our descent so had to drink very quickly!

Our first flight was delayed so we missed our connecting flight. However it was easy to book a later flight on their app.

My flight was delayed by 6 hours then I missed BOTH of my connecting flights, I then had to stay in the AIRPORT at JFK because soooooo many people also suffered from missing flights and there was no hotels available. I would like to be compensated for this experience! I had to stay in the airport for over 16 hours!

The service was great. However the lounge only gets passing grade

Cabin crew professional, polite and friendly, boarding was seemless, but come on KLM surely you can do better than a pack of cheesy biscuits as an inflight snack

Cabin crew were excellent, very proffesional, polite and friendly, in flight snack was underwhelming, a packet of cheese biscuits, im sure KLM could run to a sandwich!

Legroom not all it could be, especially when the seat in front is reclined. Otherwise it was good, food and beverage were nice.

This portion of the flight was through Indigo. A local carrier. So all economy seating. No real service some refreshments for purchase standard economy stuff.

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.

Everything was good, except the seats in economy were so close together, you could barely get out when the seat in front of your was reclined. If the airlines keep jamming in more and more seats, it will become intolerable. I will look for another airline that considers customer comfort and does not keep adding more rows of seats for more profit.

Great service on board. Boarding a bit slow due to process. Food was pretty average.

Very small cramped plane for an international flight. Everything else was good, but it was maybe the smallest comfort-wise I've ever been on for longer than 3-4 hours and the trip was 7.5

Flight was delayed 3 hours. No food and drink vouchers was provided. They offered a mini pretzel bag and water .

Staff was rude. Didn’t give water for 2 hours. Worst service

Was on time until within 1 hour of flight-how does that happen? Staff very friendly.

I liked the choice of lemon ginger tea. I think stewardesses can be more considerate of older people needs.

We were given vouchers we couldn’t use with a 5.5 hour delay

I fly UAL 7-8 times per year. This flight was not up to snuff because it boarded very late "due to unexpected delays in restocking the plane" and yet Flight Aware showed the plane had landed some 10 hours earlier--so I think they could have planned accordingly. The FA's were nice but harried. The video system had to be rebooted 3-4 times. The food service was rather abrupt; they forgot my row and when I asked for my meal, they brought it with some impatience. Overall, the flight was fine, but the little details made it feel somewhat mundane and hurried.

An old airplane with very uncomfortable seats in the Comfort “class! Small, narrow, and hard seat. Entertainment options are inferior, old movies. Boarding started at the back of the airplane, as we entered the aircraft last instead of after business class, risking the possibility that the comfort section would not have room for carry-on in the overhead bin. The food was ok. White wine was terrible. Overall, the flight felt worse than cheap airliners, and the price was as high as premium carriers.

I will avoid TAP if I can, the ground experience was very poor with bad behaviour from the ground crew and it was only a bit better on the aircraft.

I had a business class ticket from EWR to Madrid with a layover at LIS for 11 hours. It was obvious that I needed to pick up my luggage in Lisbon for 11 hours and check it in again when boarding the second flight to Madrid. Before buying the ticket, I called TAP customer service. Customer service assured me that I could get my luggage in Lisbon. When I arrived at Newark airport, I immediately asked to check my luggage to Lisbon. However, the TAP employee refused me, saying that I should resolve this issue upon arrival in Lisbon. She checked my luggage to Madrid. I asked the TAP employee at the gate to help me when boarding the plane, I asked the flight attendants manager on board the plane to help me. All the employees refused to help me and said that I should resolve this issue in Lisbon. It took me 4 hours to resolve this issue in Lisbon. I arrived at 11am and they didn't give me my luggage until 3pm. As a result, I was so tired after a sleepless night on the plane and 4 hours on my feet at the airport and all my plans were ruined that I couldn't fly to Madrid. It was a terrible experiance,

The seats were not designed to comfortably see people in coach for more than 10 minutes

A good, comfortable flight with friendly crew and good entertainment options.

Very rude person at the boarding desk; flight attendant coughing 3 inches from my face three times- not even covering her mouth; boarding process very unacceptable for older people with stairs to all planes (are you all stuck in the 1960’s?). I am sure that I am not remembering all of the negative things, but I am sure you get the message!

There was chaos at the Naples airport. We arrived three hours early for the flight but there was no invitation available about where to go to check bags until an hour later. Then we had to go to a different terminal to check our bags and check in and back to the first to board.

We flew TAP last October from Newark to Lisbon. The meal was bad. This flight had good food. Also, this flight was delayed. There were TAP employees waiting at Lisbon to make sure we made our connecting flight. I find the TAP website and app frustrating, but the service once we reached the airport was very good

The airport temperature at the airport and on the flight was too warm

Boarding too way too long. Biggest peeve: zero in-seat power in economy! No plug sockets, no USB ports. Plane was an A330, so not old.

It was fortunate that the flight arrived in London in accordance with schedule, and the luggage was promptly transferred to the luggage carousel. However, I find it concerning that even minor issues in economy cabins are prevalent within the industry. American Airlines, in particular, appears to have the least legroom and feels more crowded due to the proximity of neighboring passengers. Additionally, the crew’s adherence to protocol is inconsistent. While they may enforce certain rules set by the FAA on a select few individuals, they often overlook numerous violations, such as failing to reset seat recline during landing.

We liked the flight but while we purchased an aisle seat, our seats had a different configuration on this flight. A fellow passenger suggested that the airplane had been changed. Too bad we were not informed and had no chance to modify our seat preferences. We were stuck in the window and middle seats with no chance to walk around and go to the bathroom without disturbing our sleeping fellow passenger.

The crew were not very personable. The crew did not serve tea or coffee. The bathroom was not kept clean. Two out of the 5 toilets in the cabin weren't working.

It was extremely cold in the back of the plane. The seats are uncomfortable and space very small. Crew was excellent as usual.

Check in needed to be in person, not nice. Also I won’t do connections in Charlotte again because you need to go through security again and short connections become a problem

Iberia lost my bag, said they found it in another country, said they sent it to me, but never did. Went my whole trip without my stuff, but expecting it to show up because that’s what they said would happen. Their communication sucks, their website sucks, and to top it all off, their seats are small and uncomfortable. They’re bad at their jobs and they should feel bad about themselves. Do not even get me started on the flight home. AVOID!

I described my experience in the previous window. I didn't realize that there would be another opportunity for this flight. Please look at my response in the previous window.

Boarding was 2 1/2 late no explanation Captain said he did not know why, but he rested at home for an extra couple of hours. Food was edible, Nothing more.

I liked the comfort of the plane. It was unexpected from past experiences.

BEWARE!!! Iberia changes your seats at random. I paid for a window seat and they changed it to one in the middle aisle resting against the bathroom- can’t lean back + hear every flush. This on a 11 hour flight.. There were families that were broken up with separate seats all over the plane. Lots of upset passengers showing their seat confirmation to the besieged and helpless airline steward. Also, the gluten free meal was tasteless.

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