Frontier's Premium seats provide up to seven inches more legroom than Standard seats.
Avoid Basic Fare to select your seat and ensure carry-on space.

Planning a trip from Denver to Portland? KAYAK’s data-powered insights will help you find cheap flights. Learn the best time to fly, how early to book your ticket, and other tips to secure great prices.
When planning a flight from Denver to Portland, there are several strategies that could potentially save you money. Generally, the cheapest day of the week to fly is Saturday, and the cheapest month to fly is February.
Day Selection: Opt to fly on Saturdays for the lowest fares.
Month Selection: Consider flying in February to save on airfare.
Booking Advance: Book your flight at least 15 days in advance to get the best deal.
Airline Choice: Frontier Airlines generally offers the cheapest flights for this route.
Flight Type: Direct flights are typically more expensive, so consider flights with layovers to save money.
This feature is powered by ChatGPT: an OpenAI-developed artificial intelligence model trained with KAYAK proprietary data and third-party data not verified by KAYAK.
| Low season | February |
|---|---|
| High season | July |
| Cheapest flight | $67 |
Direct departures
Denver Intl to Portland
Monday
Alaska Airlines, Frontier, Southwest, +1 more
Alaska Airlines, Frontier, +2 more
1
Tuesday
Alaska Airlines, Frontier, Southwest, +1 more
Alaska Airlines, Frontier, +2 more
1
Wednesday
Alaska Airlines, Frontier, Southwest, +1 more
Alaska Airlines, Frontier, +2 more
1
Thursday
Alaska Airlines, Frontier, Southwest, +1 more
Alaska Airlines, Frontier, +2 more
1
Friday
Alaska Airlines, Frontier, Southwest, +1 more
Alaska Airlines, Frontier, +2 more
1
Saturday
Alaska Airlines, Frontier, Southwest, +1 more
Alaska Airlines, Frontier, +2 more
1
Sunday
Alaska Airlines, Frontier, Southwest, +1 more
Alaska Airlines, Frontier, +2 more
1
Direct returns
Portland to Denver Intl
Monday
Alaska Airlines, Frontier, Southwest, +1 more
Alaska Airlines, Frontier, +2 more
1
Tuesday
Alaska Airlines, Frontier, Southwest, +1 more
Alaska Airlines, Frontier, +2 more
1
Wednesday
Alaska Airlines, Frontier, Southwest, +1 more
Alaska Airlines, Frontier, +2 more
1
Thursday
Alaska Airlines, Frontier, Southwest, +1 more
Alaska Airlines, Frontier, +2 more
1
Friday
Alaska Airlines, Frontier, Southwest, +1 more
Alaska Airlines, Frontier, +2 more
1
Saturday
Alaska Airlines, Frontier, Southwest, +1 more
Alaska Airlines, Frontier, +2 more
1
Sunday
Alaska Airlines, Frontier, Southwest, +1 more
Alaska Airlines, Frontier, +2 more
1
Late. Too long a flight for a 737. 0.5 oz of pretzels for a 5+ hour flight at dinner time. One step above Ryan Air/ several below Delta.
Late. Too long a flight for a 737. 0.5 oz of pretzels for a 5+ hour flight at dinner time. One step above Ryan Air/ several below Delta.
Once again, Hawaiian Airlines upon checking in for our return flight, told us that we hadn’t paid for our extra comfort seats. This had happened on our incoming flight as well. Hawaiian Airlines had changed our flight and put us in standard seats. I sent them confirmation emails and receipts showing that I had paid for extra comfort seats and they ignored me and refused to accept my proof of payment. I ended up having to pay for our extra comfort seats again. On our return flight, once again, we were told we hadn’t paid for our extra comfort seats, which we had. I argued until a supervisor was summoned and researched further in their system and found that we had paid for them. If I hadn’t insisted, we would’ve been forced to buy our seats again or be assigned a standard seat. This kind of Customer Service is totally unacceptable. I would never use Hawaiian Airlines again if I have a choice.
Flight delay caused me to miss my connecting flight home, but I was put up at a nearby motel, and it was great
My seat. The reprentative on the phone was bad. The passengers screamed at each other and no one stopped them. The directions boarding the plane were unclear. There was a medical incident and the ICU nurse present said the women was having a cardic incident. Cooler heads determined it was a UTI. I had a allergy attack and a guy got a mask from the flight attendent and told me to wear it. He "had kidney failure". Why didnt they tell him to wear the mask, why was he even on the plane? It was embarrassing, he said hurtful things. By the way, I have a degree in Medical Micrbiology from Northwestern Medical school. MT(ASCP). Look it up. I Know the difference between allergies and an infection. But we had to listen to the unstable screaming man.
Wouldve liked a meal option (that you didnt have to prepay for) for such a long flight. But otherwise staff was friendly and boarding/un boarding was as efficient as it could be
The flight attendants were friendly. I liked that I got a mini soda can, not just a small cup. No issues with our flight departure, etc.
The flight was great, unfortunately the Airport sucked at accommodating connection flight. My Mother had to sleep at the airport, making me feel helpless. Unable to determine if I should sleep or drive 3 hours each way to pick her up.
The crew was the best I’ve ever had HOWEVER when we arrived in Salt Lake City there were no Alaskan Airline employees to be found so we weren’t able to leave the plane until ANOTHER airline took pity on us. How could that possible happen?
Alaska is the best! I had my own row, complimentary wine, friendly flight attendants, free texting, and early arrival. Coach felt like 1st class. What more could I ask for?
The flight was good, but your car partner, Wisecars, was worse thane awful. They didn't have an agent nor had they inform me which car rental they were supposed to have issued a voucher.
Ever since Southwest starting charging for bags, passengers don't want to pay to check their bags, so the gate agents have to beg people to check their roller bags now because there's "not enough space". This was a terrible business move by Southwest.
Full cans of soda would be nice. A choice between two snacks would be appreciated.
Tried watching free movie and it kept freezing so I couldn’t finish.
All was good. I just had a hard time getting connected to the WiFi/internet during the flight
Sacrament staff are always polite and helpful. Airport is easy to maneuver and boarding is straightforward.
Great flight. Outstanding Service. Southwest was able to put us on a direct flight to Denver when the connection could have been affected by a later arrival to Baltimore. The direct flight was less expensive that the flight with the connection in Baltimore.
Delays delays delays. Late taking off, late landing, wait for a gate, etc.
Boarded on time but once we were ready for take off, the crew determined that, although every seat was taken, somehow someone was on the wrong flight. Delay, delay delay, announcements and ended up with one person checking EVERY ID against their passenger Manifest only to figure out it was a "clerical error." We departed 54 minutes late causing me to run in the St. Louis Airport to make my connection and lose the priority boarding spot I had paid for. Unnecessary delay.
I was re-booked onto another flight because my original flight was delayed and I would have missed my connector. I ended up in the “C” group after paying extra to be in the “A “ group on the original flight. At least if you’re going to re-book people, re-book them into the same group.
Flight was delayed due to plane not passing inspection And one of the crew had to time out and we had to wait for another one A 3 hour delay
The flight was CANCELED!!! Can’t get much more “poor” than that. I had to switch to American Airlines, add another layover and got home in Honolulu 4 hours later than I was supposed to be home. One bright spot was Josh with Alaska Airlines at SFO. He got me on a United Flight that got me home a few hours before I would have. Without him I would have gotten home almost 7 hours after my originally scheduled flight.
Canceled my flight within 24 hours, causing me arriving home midnight. Will never book Hawaiian airlines anymore
I like Hawaiian, it was great that they had good internet connection across the Pacific Ocean, thanks to Star Link satellites. The seating was comfortable, ( I was in economy ). Maybe I missed it, but I only got offered a beverage once. It was a nonstop flight KOA to SMF. I would take it again next time I go that way.
I always love flying Hawaii and I have nothing to add
Previously flown Hawaiian Airlines on similar routes, I found Alaska Airlines to be noticeably more comfortable. The seats on Alaska Airlines provided better support and cushioning, which made a significant difference on the long flight to the islands. When you’re spending 5-6 hours in the air, seat comfort really matters, and Alaska Airlines delivered where it counts. After comparing both carriers, I’ve decided to book with Alaska Airlines for all my future Hawaii trips. The superior seat comfort alone makes it worth choosing Alaska over Hawaiian Airlines. If you’re planning a trip to Hawaii and prioritizing comfort, I’d recommend giving Alaska Airlines a try. You won’t be disappointed. Highly recommended for Hawaii travel!
I received several emails about my 3:10 flight. When I showed up to the airport at 12:30 to check my bags I was told the flight was actually at 1 pm. They grudgingly rebooked me for a flight at 5:22 to Vegas to get a connecting to LAX. I did find the gate for my original 3:10 flight but they were booked. I proceeded to receive status updates and gate change information for the 3:10 flight, even though I was apparently never supposed to be on that flight
My flight was delayed three hours and then cancelled. The gate agent proceeded to rebook me in a middle seat without telling me and I was placed between two large individuals who did not fit in their own seats and instead took up most of mine. It was an awful experience.
The food options were limited and very specific. Some type of entertainment option for a 4.5 hour flight would have been nice.
Flight was smooth and comfortable. We were able to check a bag at counter due to full flight and boarded with an earlier group. We were there very early and didn’t hear the gate change just noticed our flight was no longer displayed st the gate. There were two other flights with gate shuffles - may be unavoidable but not desirable. First time I had to print my own luggage tag and attach at arrival. Not a fan of that process.
The crew was EXTREMELY helpful And sweet and the flight was smooth!
Crew seemed a bit cranky. No seatback screens. But boarding was efficient and on time and we arrived early.
I will never book a flight through Cheap fare. They booked me from Portland Main . And would not give me a refund, so I bought 2 tickets one for 299. From Portland Main to ORD. Then I had to buy a ticket from Oregon PDX to ORD that was another 440. So Just so you know they even told me it was there fault but no refund. Bad bussniess. I did inform United but they said they couldn't help me due to the fact I booked through Cheap Tickets. Never again. And I'm spreding the word. I let everyone know at my 50th class reunion
See previous note about the passenger in Denver who threw my husband's bag out of the overhead bin in order to maker room for his own. And the flight attendant back up the new passenger.
Terrible. They wouldn't allow me on my flight on the 14th..
Impressed with the service despite turbulence because of the weather. Both flights arrived before their scheduled times.
Great experience…left a bit behind schedule but made up fir that in the air and landed 10 minutes early 😁
Electric plugs didn't work. Entertainment system wasn't working
The design of the light switch on the arm rest is ridiculous.
The gate attendant let me walk right by her with a bag too big for the overhead compartment
Overall, it was a good experience. Boarding was good and there was plenty of overhead bin space for everyone’s carryons (even when we boarded toward the end). Only improvement would be to offer trash service more regularly.
Frontier is the Walmart of airlines. Frontier has removed adjustability and comfort from their seats to make the flight lighter and save gas. This makes it impossible to sleep on their flights. Their customer service is abysmal. Once, I bought a drink on the plane, and they swiped my credit card on the plane to pay for it. Then I got three weeks of daily notices from my bank telling me they tried to charge the wrong card number over and over again. I tried to call them, but they removed the ability to actually talk to someone that can resolve such a problem from their company to cut corners. The only way to talk to someone in person is to go to the check-in counter at the airport (40 minutes drive from my house). Eventually their system gave up on trying to charge the card, after 21 days of repeated tries. They don't pad their prices even a little to handle customer service issues like missed flights. They also have a blanket policy preventing helping you reschedule a missed flight if their system says you "cancelled" your own flight online. This is a major problem because their website is broken on mobile devices, the only web browser you have at the airport when their gate staff tell you that you have to reschedule your own missed flight online because they can't help you. I tried to reschedule my flight on my android device and instead, their website crashed and "cancelled" my missed flight. When I got to the counter, the agent argued with me for 5 minutes insisting that I intentionally cancelled my own flight (implying I had to buy another flight). She missed the point: the problem was that I could not buy another flight because their website is broken. I left to avoid more conflict with the "customer service" agent. I tried to redress my issue with their only other "customer service" chanel available: the contact form on their website. The response I got was more of the same: you cancelled your own flight, according to our website / computer records, therefore we won't help you. I was trying to explain the problem with their broken website that cost me hundreds of dollars by crashing / malfunctioning and resulting in a cancelled flight, but they only had deaf ears for this problem. Worst customer service I have ever experienced. I will never buy another Frontier flight again, because it is a risky, painful move that I will likely regret often.
What I expected, nickeled and dined and a frontier flight attendant loudly complained about her job and lack of communication as she headed to the gate on her cell phone. Not professional.
The delay was ridiculous because nary a word escaped from the gate attendant regarding our flight status. It was a complete joke.
I’m not gonna fly Frontier Airlines because booking is not an option. No water or food is for high price, not equipped for health emergency incompetent crew for emergency services. Cheap airline shows it is cheaper in all service categories. Boarding is the best of all airlines!
Very bad! No good service delayed my second connection flight
Frontier is terrible. Paid for exit row, not given exit row, refused to refund fee.
2 hour delay due to late plane, wrong size plane causing overbooking, and people getting off and on the plane after boarding was completed.
The worst. We never made our connection and they did absolutely nothing to help us at the airport.
I never got to experience the flight because they delayed my first flight and I missed this one. Then Frontier didn't want to help me rebook a flight to get me to my final destination.
The Boarding process in Denver was chaotic, and since the line was so long, we were lined up very far from the gate. If there were any announcements from the gate staff, we didn't hear them. The flight attendants were spectacular. The only negative part of the flight was sitting by a 2 1/2 year old who was unruly and unfortunately had parents that matched his behaviors. Also, the restaurants in Denver on the E concourse, they didn't have food (passengers could only order 1 item on the entire menu) or the restaurants had 12-14 people waiting for orders to be prepared and another 6 people waiting to order. If you have a layover in Denver and need to grab food, be prepared to visit the shops with pre-packaged sandwiches, or you can visit another concourse but it may take a while to transit throughout the airport.
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