IAD - OPO

$257 Find Cheap Flights from Washington Dulles Airport to Porto - 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 Dulles Intl to Porto departing on 8/28. 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
$805
Typical prices: $595-$747
United Airlines
Mon 9/28Fri 10/9
IAD - OPO • 2 stops
Cheapest one-way
$257
Typical prices: $463-$558
Multiple Airlines
Fri 8/28
IAD - OPO • 2 stops
Top airlines
Cheapest • from $805 (round-trip)
Best reviews • 7.8 score
Airline reviews
Airline reviews
+1
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Airline reviews
Airline reviews
+1
Nonstop flights
Not available
There are currently no direct flights between Dulles Intl and Porto. You'll need at least 1 connection.
Insights
Insights
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Insights
Top layover airports
Cheapest • Avg $612 (round-trip)
Shortest trip • 9h 47m (one-way)
Insights
Insights
Insights
Insights
When to book
in advance
Our data shows that travelers who book at least 2 weeks in advance save around 24% compared to booking last minute.
Insights
Insights
Insights
Insights
When to travel
Cheapest • 35% price drop
Most popular
Good to know
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+1
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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

Mon, Sep 28 - Fri, Oct 9
United Airlines Logo
10:25 pm - 7:00 am
IAD
-
OPO
27h 35m
2 stops
United Airlines Logo
6:00 am - 10:59 pm
OPO
-
IAD
21h 59m
2 stops
$805United Airlines
Thu, Aug 27 - Sun, Sep 20
TAP AIR PORTUGAL Logo
10:35 pm - 6:55 pm
IAD
-
OPO
15h 20m
1 stop
TAP AIR PORTUGAL Logo
9:15 pm - 3:10 pm
OPO
-
IAD
22h 55m
1 stop
$806TAP AIR PORTUGAL
Mon, Sep 28 - Tue, Oct 6
Air Canada Logo
9:45 am - 11:25 am
IAD
-
OPO
20h 40m
2 stops
Air Canada Logo
6:00 am - 9:24 pm
OPO
-
IAD
20h 24m
2 stops
$807Air Canada
Sun, Aug 16 - Mon, Aug 24
TAP AIR PORTUGAL Logo
5:40 pm - 10:00 am
IAD
-
OPO
11h 20m
1 stop
TAP AIR PORTUGAL Logo
6:00 pm - 3:10 pm
OPO
-
IAD
26h 10m
1 stop
$808TAP AIR PORTUGAL
Tue, Aug 18 - Mon, Aug 24
Multiple Airlines Logo
8:25 pm - 5:50 pm
IAD
-
OPO
16h 25m
1 stop
Multiple Airlines Logo
8:15 pm - 3:10 pm
OPO
-
IAD
23h 55m
2 stops
$809Multiple Airlines
Fri, Sep 25 - Fri, Oct 9
Multiple Airlines Logo
8:30 pm - 9:25 pm
IAD
-
OPO
19h 55m
2 stops
Multiple Airlines Logo
7:35 am - 7:00 pm
OPO
-
IAD
16h 25m
2 stops
$810Multiple Airlines
Wed, Aug 19 - Mon, Aug 24
Multiple Airlines Logo
5:00 pm - 10:10 am
IAD
-
OPO
12h 10m
1 stop
Multiple Airlines Logo
8:15 pm - 3:10 pm
OPO
-
IAD
23h 55m
2 stops
$811Multiple Airlines
Wed, Aug 26 - Mon, Sep 21
TAP AIR PORTUGAL Logo
10:35 pm - 5:00 pm
IAD
-
OPO
13h 25m
1 stop
TAP AIR PORTUGAL Logo
5:05 am - 3:10 pm
OPO
-
IAD
15h 05m
1 stop
$812TAP AIR PORTUGAL
Mon, Oct 5 - Mon, Oct 19
Multiple Airlines Logo
8:28 am - 7:00 am
IAD
-
OPO
17h 32m
2 stops
Multiple Airlines Logo
10:10 am - 2:00 pm
OPO
-
IAD
32h 50m
1 stop
$813Multiple Airlines
Wed, Aug 19 - Mon, Aug 24
Multiple Airlines Logo
5:35 pm - 12:05 pm
IAD
-
OPO
13h 30m
1 stop
Multiple Airlines Logo
7:20 pm - 4:45 pm
OPO
-
IAD
26h 25m
1 stop
$814Multiple Airlines
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?

This analysis is based on the cheapest round-trip price found on KAYAK in the last 12 months by searching for a flight from Washington, D.C. Dulles Intl Airport to Porto departing in September.

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 May and June, where the average cost of round-trip tickets is $1,227 and $1,069 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 2 weeks before departure, which saves you about 24% 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$257
Best time to beat the crowds with an average 25% drop in price.
Most popular time to fly and prices are also 7% lower on average.
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 5 days, the lowest price for a flight from Washington, D.C. Dulles Intl Airport to Porto was $257 for a one-way ticket and $805 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 $1,048 and an overall rating of 7.8, Delta is the most popular choice. KLM is also a great choice for the route, with an average price of $883 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.
7.8
DeltaOverall score based on 8452 reviews
7.8Comfort
7.2Food
8.1Boarding
8.5Crew
7.8Entertainment
Airline reviews

Everything about this flight was good except for the very end when I reached my destination. Everyone from the tune to the wheelchair escorts were great with the case were great but I miss you with people at the check in this at the very end. I need help from the chicken desk because I forgot my pillow on the plane The female worker at the chicken desk said that they found my pillow and she was going to retrieve it for me. She left a 30 minutes without any update and her so she saw me walking back and forth waiting for her and they didn't even bother calling her or radioing her for any updates. They were busy because they were behind schedule and they were overwhelmed but thanks because at least glanced me and try to give me an update just a quick radio check or phone call. I don't care about the pillow but if you tell me to wait, I waited for at least half an hour before I said something and I just left because they wouldn't bother talking to me so I could, so everything's going in the review. I took pictures of the two men that were left working at the check-in counter. The totally ignored me despite the signals I've been giving them. I don't see any offers in the kayak review to add pictures or screenshots so I'm going to post another review I don't know their name but I'm pretty sure Delta will find other names when they see the review. Google with pictures. There was another guy at the chicken counter bring an orange workers vest who finally left after telling me that the girl that was retrieving my pillow is working the gates now. That would have been if they just told me that's what happened. But I had no update. Make me wait for nothing. Thank you Delta airlines!

6.0 GoodNghia, Jun 2026
DTW - OMA
Read more Delta reviews

Everything about this flight was good except for the very end when I reached my destination. Everyone from the tune to the wheelchair escorts were great with the case were great but I miss you with people at the check in this at the very end. I need help from the chicken desk because I forgot my pillow on the plane The female worker at the chicken desk said that they found my pillow and she was going to retrieve it for me. She left a 30 minutes without any update and her so she saw me walking back and forth waiting for her and they didn't even bother calling her or radioing her for any updates. They were busy because they were behind schedule and they were overwhelmed but thanks because at least glanced me and try to give me an update just a quick radio check or phone call. I don't care about the pillow but if you tell me to wait, I waited for at least half an hour before I said something and I just left because they wouldn't bother talking to me so I could, so everything's going in the review. I took pictures of the two men that were left working at the check-in counter. The totally ignored me despite the signals I've been giving them. I don't see any offers in the kayak review to add pictures or screenshots so I'm going to post another review I don't know their name but I'm pretty sure Delta will find other names when they see the review. Google with pictures. There was another guy at the chicken counter bring an orange workers vest who finally left after telling me that the girl that was retrieving my pillow is working the gates now. That would have been if they just told me that's what happened. But I had no update. Make me wait for nothing. Thank you Delta airlines!

The gentleman at the gate I think his name is RIE was exceptional

This flight was no comparison to our prior flight. I'm thinking it all has to do with the age of the aircraft.

2 of the seats in row 31 the entertainment system was not working, and one seat the tray table did not go all the way down. Flight arrived early and departed on time which was great.

Waited at the usual crowded gate at DCA where one ends up standing up because there aren't enough seats.

Delayed take-off. Very small plane so very scary with lots of bumps during the flight. Would never fly Delta on short flights in small 80 seaters plane again! Felt relieved when landed.

Inexpensive, got an exit row aisle aeat with no middle passenger, bought a great breakfast sandwich, flight comfortable & arrived ahead of schedule.

Overall Delta was amazing from automatically booking us on the next flight once we missed our connection due to a delay to the constant communication throughout the entire process. We will continue to fly Delta going forward more and pay a little more if needed.

I wouldn't say I liked being forced to check my small roller bag at the gate; too many people had bags and were in a higher boarding group.

715PM departure was 2.5 hours late. Received hotel & food voucher but after we already booked a room. Entire team just seemed like they were 2-3 steps behind in execution, and notifcations.

Staff could’ve been a little more cordial. The men were much more friendlier than the women. My daughter and I also missed the 2nd to last meal as we were sleeping but that is on us.

Like: departed and arrived on time. Unlike: Food options for purchase allways bad, 1 of 2 of the crew members not very friendly at all. Seats and leg room aweful. At this point I am thinking on switching to AA.

Our flight was canceled same day and we were never informed. Had to pay more and worse seating on another airline.

Did not like that we couldn't complete check in on-line without providing pictures of our passports. Worry about identity theft. We had no delays and boarding was handled In an efficient manner.

Excellent! I got to Munich and was transferred to my Lufthansa flight quickly, in 15 to 20 minutes, so I did not miss my flight. However, I had checked my overhead bag at the boarding gate in Tampa. That got to Tunis the next day. That is to be expected.

WiFi didn’t exist , seats were super cramped, lights stayed on near my seat for a long time while others were dimmed, the food/trash/drink cart hit my shoulder at least a couple of times while moving, food options were down to just one option by the time it got to my row, the utensils were garbage (knife bent at a couple of places by the time I was done eating) the spoon was very flimsy plastic

Vegetarian selection could be better. Bread was too hard to chew.

Crew was friendly and competent. Food, wine, and entertainment were excellent except the raw tuna on the flight to Split. Recommend against serving that - at least as the only option. Many medical conditions do not allow people to eat raw fish.

United didn’t even try to hold the flight for me. They knew I had a tight connection and when I arrived at the gate less than 10 mins after final boarding the flight had already gone. The gate agent wasn’t even notified that I was on my way. She was told I wasn’t at the airport

Food was poorly timed and not good.. Hand held snacks, really. I kept asking for water and never got any. Service was rushed for a 7-hour flight.

The flight crew were absolute rock stars. When they came to the gate they looked like royalty, so chic. They also were extremely kind. Food was good and I loved the lack of plastic waste. The flight was lovely and smooth.

We were unable to check in due to technical problems on TAP’s end. The flight was delayed forty minutes with no reason given. We received timely notice of the flight delay. We were also notified of a gate change. The new gate was at a different terminal. When we got to the new terminal, we learned that we had to go back to the old terminal first to check in. This information should have been included along with the gate change notification. Also unexplained, the steward skipped us when offering breakfast.

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.

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

Checked bG chstgr was extremely high. Over $120. It was s bsit and switch knowing an international passenger would have t9 check a bag.

On time, politeness, food okay but entertneiment mediocre with only old movie and the so called new we’re 2 or 3…

Our flight from NY was on time. The leg room was torture.. for a long flight.. It was extremely uncomfortable.

Everything went very well. I would like to acknowledge the politeness and professionalism of the staff—they are superb. No complaints.

No legroom, have to pay for everything including water?!? Water is more expensive than beer?

We liked the crew. They were competent, professional and friendly. The only big negative was our departure was delayed several times and the airport staff did not communicate what the problems were and what we should expect.

The flight was operated by level, who had a sister’s check in procedure (2 hours) due to understaffing and a computer malfunction. While 3 agents stood at the business check in, with a total of maybe one actual customer there at a time, a huge line formed at economy check in with only 1 agent staffing the check in. Then, my luggage was lost - a guitar case with contents inside valued at 3,000 USD. The computer system of LEVEL could not locate my bag and had no record of it, and IBERIA (with whom I purchased my ticket and the checked bag) refused to help. It was a disastrous experience and I will never book Iberia again

Not bad but they lost 2 of my bags when I got to Florence

Puddle-hopper. Quick-ish flight. Don’t expect to have much/any in-flight entertainment (movies/TV, etc).

Couldn’t get boarding passes online, delayed an hour, and smallest amount of space on board I’ve ever encountered for such a long flight.

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.

online check-in was horrible and didn't work either way

Its a bus taking you on and off the plane so if you have big luggage … more muscles needed

Terrible. Boarding was a mess. We were assigned middle seats and separate just to induce us to pay for better seats. Cabin luggage was checked in while space remained on the overboard lockers. I think they don't really care about the customer.

The trays weren’t wiped. They still had food from last passengers

I called prior to flying to confirm our baggage allowance which was 5 bags. On our outbound flight thee were no problems. On the return flight we were charged for each bag totaling $400! We are working with customer service to resolve the issue.

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.

The flight and crew were good. The customer experience on the ground could have been better. We had to reschedule our flight because of a delay on the previous flight. The attendants working the desk in Washington DC were not helpful. They told us to scan a QR code and that would get us rebooked. Why couldn't two people standing at their computers do this? We had to chat with someone to get everything figured out. It was extremely confusing.

good entertainment package but rather small seats for business class

The male attendant has zero personality. It seemed like he was over worked or hated his job, not once did he smile or made any contact with the people on the plane. Strictly business and call it a day!

Our flight was delayed for over an hour due to weather, and it had already been a long travel day. However, the crew was calm and compassionate, listening to every complaint with genuine concern. They got us home safely without incident, in spite of all of the obstacles. I’m grateful.

Bad! Disaster!! The LH419 was cancelled after 4 hrs on board with no AC and no toilets

We had almost a 6 hr delay, primarily due to weather, the e problem was that they communicated this delay and its length very poorly. The boarding was chaotic - even though they had hours to figure it out! The plane was an old 747 whose touch screens barely worked and there was a faulty USB port under my seat rest (something that wasn't labeled as being there) They organized my delayed luggage well. And I could get updates on the Lufthansa website. My shirt connecting flight charged for everything except water. Coffee was over 3€

It was freezing. I asked crew member for a blanket and was told it might be in front of plane but I never got one. I turned off all the vents but still froze.

My schedule flight was rebooking and changed to Chicago, then I did not used the flight from Dulles to Savannah

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

Information on your arrival and departure airports