Frontier's Premium Bundle includes priority boarding and extra legroom for a small additional fee.
Frontier charges for carry-on bags, so consider the Economy Bundle for a free carry-on.

Planning a trip from Sky Harbor Intl to Seattle? 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.
Traveling from Phoenix Sky Harbor Airport to Seattle can be more affordable if you know when and how to book your flight. Generally, Tuesdays are the cheapest day of the week to fly, while September is the cheapest month.
Day Selection: Choose to fly on Tuesdays for the best rates.
Month Selection: Opt for September flights for lower prices.
Booking Advance: Book your flight at least 64 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, 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 | January | 
|---|---|
| High season | July | 
| Cheapest flight | $51 | 
Direct departures
Phoenix Sky Harbor Intl to Seattle/Tacoma Intl
Monday
Alaska Airlines, American Airlines, Delta, +2 more
Alaska Airlines, American Airlines, +3 more
1
2
Tuesday
Alaska Airlines, American Airlines, Delta, +1 more
Alaska Airlines, American Airlines, +2 more
1
Wednesday
Alaska Airlines, American Airlines, Delta, +1 more
Alaska Airlines, American Airlines, +2 more
1
Thursday
Alaska Airlines, American Airlines, Delta, +2 more
Alaska Airlines, American Airlines, +3 more
1
2
Friday
Alaska Airlines, American Airlines, Delta, +2 more
Alaska Airlines, American Airlines, +3 more
1
2
Saturday
Alaska Airlines, American Airlines, Delta, +2 more
Alaska Airlines, American Airlines, +3 more
1
2
Sunday
Alaska Airlines, American Airlines, Delta, +2 more
Alaska Airlines, American Airlines, +3 more
1
2
Direct returns
Seattle/Tacoma Intl to Phoenix Sky Harbor Intl
Monday
Alaska Airlines, American Airlines, Delta, +2 more
Alaska Airlines, American Airlines, +3 more
1
2
Tuesday
Alaska Airlines, American Airlines, Delta, +1 more
Alaska Airlines, American Airlines, +2 more
1
Wednesday
Alaska Airlines, American Airlines, Delta, +1 more
Alaska Airlines, American Airlines, +2 more
1
Thursday
Alaska Airlines, American Airlines, Delta, +2 more
Alaska Airlines, American Airlines, +3 more
1
2
Friday
Alaska Airlines, American Airlines, Delta, +2 more
Alaska Airlines, American Airlines, +3 more
1
2
Saturday
Alaska Airlines, American Airlines, Delta, +2 more
Alaska Airlines, American Airlines, +3 more
1
2
Sunday
Alaska Airlines, American Airlines, Delta, +2 more
Alaska Airlines, American Airlines, +3 more
1
2
I wish my checked suitcase could have been checked since I arrived an hour before take off .
I wish my checked suitcase could have been checked since I arrived an hour before take off .
The staff was so kind and friendly! Boarding was efficient and communication was timely. I would seek out flying with Alaska Airlines in the future.
The cabin crew on this team was particularly kind and excellent.
Check in went pretty well and you didn't lose my bag. After I got a drink from the drink cart they charged me for it, and at the crazy overpriced airport rates. Never had that happen before, is that an american thing? what madness.
In both halves of the trip (going and returning) there were problems. Not exactly Alaska's fault, but still really difficult. Outgoing flight was canceled and rebooked twice due to a total ground stop of all Alaska's flights. This required me to change airports with minimal notice and I almost missed my flight transferring to the other airport (which was roughly an hour and a half away). On the return, the first leg was delayed by an hour, and the second leg was delayed by nearly 3 hours. This was a rough set of flights and the communication about all of these changes was minimal. Crew did their best however, so no fault there. Other thing to remember is there is no food on Alaska flights unless you pre-order. Take that into account when you choose airlines.
My flight was canceled because of an IT outage, and they did not answer the phone for 8 hrs. There was no next flight out, I have missed my wedding because of this.
Liked the crew. Multiple delays. Altered my complete day and plans
Apart from the man snoring very loudly across the aisle from us for about 3.5 of the 5 hour flight it was a great flight. I couldn't get the internet to work and stay working. Texting was intermittent for me.
The plane boarded late and arrived late which wasn't really ideal.
The pretzels have no taste. How about a choice of snacks? The flight itself was fine.
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
I truly love flying with Delta. They have always treated me with the upmost respect
Our flight attendant in FIRST CLASS was one of the worst I’ve ever had. She was not at all pleasant, nor particularly good at her service.
Everything went well and was good. Nothing exceptional, but no complaints either. Cheap seats are pretty comfortable.
DELTA does a terrific job making sure you are well taken care of during the flight, gives you assurance before the flight through numerous email notifications about your upcoming flight & lastly good follow up after the flight making sure your needs were mat. It has been, is & will continue to be my carrier of choice in all my future travels. Good Job DELTA
Staff were friendly and happy. Delta could make sure passengers that don't have the app know of changes. Without Kayak I would not have known about the change of gate or the delay. Kayak was faster to notify me.
They ended up paying for the bag twice, but the counter wouldn't take my baggage receipt. Left it to me to resolve. Not sure how to resolve the issue.
The customer service before board was very rude and when I expressed my concerns about making the connecting flight she laughed and told me I bought the wrong ticket. I explained once it showed the flight was delayed it no longer let me change seats or anything. I was trying to upgrade to make sure I would get to the next gate on time.
Non stop on long haul is the way to go. Great experience
The flight used a B767 with a very old interior from before 2014. The entertainment system did not work at all during the flight despite attempts to reset the system. It was like they flew this route just to be competitive.
They changed planes and the new plane couldn’t carry enough fuel to fly across the country so we had to stop in Kansas City to refuel. Flight was delayed .
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
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.
Terrible. Flight cancelled with no reasoning and no flights to rebook. Employees were useless and did nothing to help. Did not even know where to retrieve luggage from the cancelled flight. Flyers beware.
No fault of Frontier staff: plane was very late, reached Orlando at 1 am, took a while to get luggage. Weather, gov financial shutdown impact on TSA, air controllers seemed to have multiple flights backed up. Frontier staff seemed to cope as gracefully as possible. It did reassure me that I and my new hip could adapt to travel challenges. Food/entertainment were irrelevant to my trip.
Terrible. The canceled my entire flight when I requested a refund for a trip frontier canceled trip one way.
Boarding was on time and plane departed as scheduled. There are obviously no amenities (food, drink, entertainment) on Frontier, but there also didn't seem to be any issues with luggage space either.
Inbound plane was on time and flight departed on time with no issues while boarding.
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!!!
i was unable to check in the flight. refund requested
It was well done. It was my first time flying with them and I was nervous b/c I have heard of many cancelled and/or delray flights. Everything went smoothly.
Just know that everything, and I mean everything is “ala cart”. 60$ just to put something in the overhead bin. I will never fly Frontier again nor do I recommend them to anyone else.
The single worst check in experience I could imagine. I’ll never do any business with Frontier or any affiliated company
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