Frontier's Economy Bundle includes a carry-on and seat choice, ideal for budget-conscious travelers.
Avoid Basic Fare to ensure seat selection and avoid middle seats; consider Economy Bundle for better value.

Planning a trip from Portland to Denver? 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.
| Low season | February |
|---|---|
| High season | July |
| Cheapest flight | $48 |
Direct departures
Portland to Denver Intl
Monday
Alaska Airlines, Southwest, United Airlines
Alaska Airlines, Southwest, +1 more
Tuesday
Alaska Airlines, Frontier, Southwest, +1 more
Alaska Airlines, Frontier, +2 more
1
Wednesday
Alaska Airlines, Southwest, United Airlines
Alaska Airlines, Southwest, +1 more
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
Denver Intl to Portland
Monday
Alaska Airlines, Southwest, United Airlines
Alaska Airlines, Southwest, +1 more
Tuesday
Alaska Airlines, Frontier, Southwest, +1 more
Alaska Airlines, Frontier, +2 more
1
Wednesday
Alaska Airlines, Southwest, United Airlines
Alaska Airlines, Southwest, +1 more
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
I liked that I made it onto the flight rather than “missing” the connection. We left PDX early in the morning along with half of Portland arriving at about the same time as we did- 2 hours prior to our flight leaving. The layover was for less than an hour and we were concerned that we would not make the connection, but as it turns out, the flight leaving LAX was even more delayed in departure due to needing some maintenance repair for the a/c of the plane. As for the food- it seems not so very nice that you are not feeding people and offering complementary alcohol on the international flights any more.
I liked that I made it onto the flight rather than “missing” the connection. We left PDX early in the morning along with half of Portland arriving at about the same time as we did- 2 hours prior to our flight leaving. The layover was for less than an hour and we were concerned that we would not make the connection, but as it turns out, the flight leaving LAX was even more delayed in departure due to needing some maintenance repair for the a/c of the plane. As for the food- it seems not so very nice that you are not feeding people and offering complementary alcohol on the international flights any more.
Flight was delayed but still made it to Phoenix on time. Boarding went quickly, the flight was smooth.
The food selections were not good, and entertainment was non existent.
I would have liked if the flight existed. To be fair the federal government canceled it. But, since it WAS canceled, I would have liked it if Alaska Airlines had moved a finger to assist me rather then abandoning me with my luggage, unable to check it, for 14 hours in Portland. So federal regulations forbid them from storing my bag? Then at least help me find storage or SOMETHING.
It was all good, no delays which was a worry. All great
It was a pleasant experience. Considering we paid over $3000 for first class there really wasn’t anything special about first class. All the seats looked the same and everyone got the same great customer service. The only thing that was different between first class and couch was the drinks and the meal. We wouldn’t waste that much $ on first class on that plane again.
Sitting on the ground for 2 hours waiting for a gate wasn't fun.
This was more with the third party booking through Kayak but my KTN for Pre-TSA, even though I entered it, wasn't assigned to my ticket when I got to the airport. I had to go through regular security. Also the Alaska app had trouble loading my ticket in the first place and I had to ask for it to be printed. Alaska Airlines was great but wanted you to know about this hiccup in the ticketing interface.
The crew was great! Passengers were nice. Just an fyi that I heard several of them complain that the snack was not gluten free. Many people got handed the snack and then promptly gave it back to the flight attendant. Might be good to look into another option as such a high percentage of people in CO and WA are gf. Cheers!
Process of checking bag, boarding, etc. was all very quick, easy, and streamlined. Only problem I had was the seating: very cramped and uncomfortable, but I suppose that’s the perils of coach. Thankfully it wasn’t a super long flight so it didn’t ruin the experience overall.
They sent a notice that they were boarding an hour early. We had to leave the club and run to the gate. They said sorry, that came from corporate and was a mistake. They did not have enough seating because the flight before it had not taken off on time. They moved our gate and delayed it for an hour.
The boarding and seat assignment system no longer works for me, but I know it is being replaced. Otherwise, I am good with the overall experience.
The lead steward kept singing about "San Francisco" and hotel California---more annoying than humorous....needs work. Flight was smooth and on time.
Still a fan of open seating. Flight was on schedule and arrived on time. The 737 MAX is very comfortable.
Airline travel is always too cramped to really be pleasant, but the cabin crew on this flight did a pretty good job of making up for it by putting on some music during boarding and sprinkling a few funny remarks into the safety briefing and announcements, and just generally being friendly and helpful. It definitely reminded me of why I prefer the in-flight experience on Southwest!
No delays and arrived to destination 30 min early. Staff was super friendly.
San Diego airport is brand new, spacious, airy and very smooth checkin at SW baggage drop.
It was rough. The staff was unprofessional, the choice of on board drinks terrible, it was cramped in space at every airport, they always ran out of overhead bin space so they pressured people to check bags for free or we couldn’t leave on the plane— so I did check my bag to help, and they nearly lost my bag. My bag did not arrive on the luggage belt, another man on my flight and I had to waste our time going to the baggage office to search for our bags. I would only fly southwest again if it was my last choice. Also, my flights were consistently delayed over and over again— at one point they straight up told us we were waiting for the pilot to arrive.
Crew could have been friendlier, maybe I'm spoiled by SW crews. In flight wifi was good. Would be nice to have more food offerings on a 4 plus hour flight
Had to get off plane from prior flight even though I had to reboard same plane to continue to my final destination.
Flight scheduled to take off at 5.55pm but it did not take off until 7pm due to some food delivery delay.
Unfortunately, I was put into the middle seat in the first row of premium seating. Sounds nice right? No! that is the worst seat in the plane. I wish I was in economy rather than be in that seat! There is no seat back pocket, no tray table, no charger. Nothing! so unless you're row mates are willing to let you share their basic amenities any flyer should have, you are stuck. It was the worst experience ever! And the flight attendant forgot to take my drink order. I felt like the forgotten flyer.
Delayed and cancelled flights were hard and very stressful, both ways!
The crew was quite good, they came by often with drinks or to collect trash. But what wasn't nice was the flight was over weigh and several people had to be rebooked. I was questioned whether I should have a seat when I was getting to it. The in-flight entertainment kept buffering and interrupting. And the route took the airplane through high winds which caused us a longer flight
Wasn’t on the flight due to Alaska cancellation…also after all the rerouting, I was going to be on a later flight that left SFO at 7:47pm, which meant an almost 6 hour layover. That same Hawaiian flight was delayed for another 2hours.
I had to cancel the flight because with a 3 hour delay for 'unexpected maintenance' in getting to LAX, I couldn't connect to an overseas flight that I had booked on Scandinavian Air.
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
United have really come back. Airport and boarding process is clear and good, app and information also very good
The entertainment available didn’t work for anyone on the flight. Long 6 hr flight with no entertainment option and the staff didn’t know until an hour into the flight when we made sure they knew about it. They had no way to fix it.
Late FA meant slow boarding. WiFi did not work. I’m a medium plus sized passenger. The seatbelt was for the first time ever barely fitting. And we delayed on the tarmac 40 min
My husband and I had boarded the flight from Denver to Chicago, and one of the last passengers to get on the plane opened the overhead bin above my husband's seat and threw his bag out of the bin to make space for his own. He said, "Mine is bigger!" The flight attendant supported the new passenger. They didn't care that my husband has two artificial knees and must have the foot room in front of his seat to be able to fit his legs in -- and to be able to stand, much less walk, at the end of the flight. I have never seen this happen before, and it was a disaster.
I understand stuff happens, but plane failures are likely due to lack of maintenance. Additionally, air conditioning wasn't working, no snack/drink service, no WiFi. Fortunately, the crew was communicative and light-hearted. United grabbed another plane and we were able to get to our destination.
Had to cancel first flight because Airporter Bus took over 3 hrs to get to airport which resulted in an extra $378 dollar fare . Is there anyway I can be reimbursed for initial fare since it was not my fault? Sent from my iPhone EJ Ledet
Excellent flight. Boarding was efficient and departure was on time. Smooth flight with on time arrival. Deplaning was also efficient.
Our flight was understandably diverted to a small regional airport in Laramie, Wyoming due to weather conditions, which I fully recognize and appreciate. However, the low rating stems from the experience that followed: passengers remained on board for over an hour without the option to deplane and stretch, despite the aircraft being stationary. Although the pilot opened the cabin door, only he was permitted to exit. Meanwhile, passengers grew increasingly uncomfortable as warm summer air entered the cabin through the open door, and being in the second row meant we were impacted immediately. While the flight attendants made efforts to keep everyone at ease, I believe allowing passengers to deplane briefly, given the extended delay, would have significantly improved the overall experience.
I never flew. Flight was canceled. DIA worst airport in the country. Avoid at all costs.
Very rough getting into denver. my kid threw up it was so rough.
I knew going into this that Frontier, being a low cost carrier, would be pretty bare bones and charge for most extras but this was made up for by the fact that the airplane was a reasonably new Airbus, every employee was great and best of all, Everett Washington is an amazing airport - thanks Frontier for flying there!!!
Seats were new and comfortable. Staff was fine. Missed my connection due to weather -which wasn’t their fault- but got no help at all. Gate staff sent me to customer service, which was and stayed unstaffed. Sign with QR code directed me to call or chat. Chat was useless. Call was returned after an hour. No itinerary offered by Frontier could get me home in less than 30 hours. Rebooked with another airline and got a partial refund that came to about 10 percent of what I paid to get home.
The experience was good. No frills but I got there safe and sound and on time.
As every law enforcement agency I could imagine surrounded the plane and we didn’t disembark for 2 hours and then had to stick around for another hour to go get our personal belongings after leaving them behind and being bused away from the plane, it was scary and inconvenient. We were given no information as to why this was happening. Lack of communication with passengers was disappointing.
Frontier Airlines was AWFUL. I was an hour early for my flight and the lady refused to check me in. I had to purchase a whole new ticket with a different airline.
Late, terrible communication, horrible planning of passenger seating until the literal last minute. One of the worst flying experiences of my life. Y'all suck
First of all, we never got on the connecting flight to Denver. They delayed our flight for two hours. If we would have gotten on that flight, we would have been stuck in Denver for 13 hours. So we re- routed our flight for a straight through flight to Oklahoma two days later. THEN, they delayed that flight for two hours. After that we were able to finally get on our flight and come home. Frontier Airlines - one of the worst airlines I have ever been on.
Terrible communication with weather delay, lost baggage, near impossible to reach customer service
My tickets got canceled on me by your site and I didn't have a flight. Then you kept sending me emails on the status of q flight I didn't have tickets for.
Flight was late. Missed connecting in Denver. My new flight is more than 24 hours later and I have no room, vouchers, or compensation, and might also be bumped from the one tomorrow.