Frontier's Premium Bundle includes priority boarding and extra legroom seats for a small additional fee.
Frontier's Basic Fare includes only a personal item; carry-ons cost extra.

Planning a trip from San Diego 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 | April |
|---|---|
| High season | November |
| Cheapest flight | $48 |
Direct departures
San Diego 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
Direct returns
Denver Intl to San Diego
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
Check in online didn't accept my confirmation number so i could only check in with assistance at the airport and ended up with s creepy middle seat.
Check in online didn't accept my confirmation number so i could only check in with assistance at the airport and ended up with s creepy middle seat.
It was the most expensive Alaska Airlines ticket I’ve ever purchased. I had a middle seat with no legroom or space compared to any other middle seat I’ve hadThere was a silver box under the seat that took up 70% of my legroom on the most narrow 737 max the crew flat out would not help they would not help with bags they would not help with garbage there was no coffee,It was definitely not one of my better experiences on Alaska.
Sitting on the ground for 2 hours waiting for a gate wasn't fun.
It was a great experience, friendly staff and good snacks
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!
Very mediocre, and disappointing for the price of the ticket
My flight wait is 3 hours delayed due to Unknown reason. We waited a very long time in the tarmac. Our flight 24 was scheduled @ 7, therefore we left my house at 330 to park our car. We were at the gate @ 530, then we were told at 6a that it will be late , we boarded at 930 but did not take off until 1015. Therefore my arranged pick up in JFK was cancelled because of no show. Before all these I got an email offers of changing my flight to a different date which I took a day earlier. I will never again take Alaska Airlines, very Inefficient and Disappointing.
Such great crew, from checkin to the plane. So friendly and helpful, I was genuinely impressed.
Seats extremely uncomfortable, no entertainment, no snacks, and when boarding, half of the passengers needed to check in the carry on luggage without any explanation.
First time flying with Alaska, and it went great. Thank you for a great experience flying to PDX.
Sacrament staff are always polite and helpful. Airport is easy to maneuver and boarding is straightforward.
As always, the entire Southwest experience was wonderful, from online booking to flight to baggage retrieval. Very grateful.
The weather could have been better. There was a 40 minute ATC delay in SFO because of marine fog and a micro cell storm delayed landing and take-off at Nashville. The gate was changed 5 minutes from boarding from gate B3 to gate C23 at Nashville airport.
Near 4 hour flight with only 1 service. Had to use call button to request water. Internet and power not working until into flight. Internet would stop working during flight.
The cabin was quiet for the redeye flight. The area was clean. The staff was great. The 787 Max was in good condition. Drawbacks were that the seat widths were tight for some passengers. The seat padding was at best average and for a long flight uncomfortable.
The Southwest employees (all two of them) were very nice and cheerful despite the fact the line to self-check a bag (simply drop it off) was hundreds of people long. Thank God I arrived early to the airport because I stood in this line for at least an hour. Once on the flight that had been delayed by an hour, we had no Wi-Fi and thus no entertainment. Finally, I hope the investor strong arm tactics against Southwest pay off in a short-term windfall to your C-Suite because the rest of you are screwed. I have been a faithful Southwest customer for 15 years due to everything you just got rid of. I'm flying to Idaho and Washington in October, both places I used to simply book with Southwest without a second thought now with Frontier (Washington) and United (Idaho) because they offer everything the "new" Southwest does but cheaper and at better times, destinations, etc. This really makes me sad...
Delayed flight. Nicest crew member was a SW pilot flying seated next to me who kindly move to seat the final passenger. Flight extra delayed. My cup of refreshment of ginger ale was so packed with ice it was literally 2 sips.
No trays in our seats, we sat in first row, purchased a business class fare. Had to hold our drinks and snack in our hands. No plugs for our cell phones. Had to pay for it a drink cocktail each. Seats so uncomfortable.
Flight wasn’t even full, but too many carry-ons caused us to run out of bin space. New bag fee has folks who would usually check their bags carrying on. Watching Southwest morph into Spirit/Frontier is so sad to watch
Flights delayed by 4-6 hours. Boarding was a mess and unclear. Bags were not at arrival airport and had never even been put on the plane. No idea when I’ll get them. Don’t fly into Denver!
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
The food options were limited and very specific. Some type of entertainment option for a 4.5 hour flight would have been nice.
The Kayak confirmation number did not work for checking in the day before. I checked in at 8.30 using my ticket number. When I arrived at the airport, I was informed that the flight was overbooked, and since I had checked in late, I did not have a seat. The Next flight was not until ten PM. I called my wife, who had been taking care of our kids all weekend, and she was upset, calling me a liar and telling me to stay in SD. It turned my weekend getaway into a nightmare! I blame the Kayak website and will not book flights using your app in the future.
comfortable but the food is horrible. I have flown Hawaiian several times now and no matter what they say the food is its the same squashed bread with melted goop inside. Tastes fake and isnt what they represent, its quite nasty. What happend to real food? And there is NO entertainment!! so not sure why they are asking for a review on that.
Good and friendly staff. Nicely enjoyed the complimentary drink and snack.
I was very, very cold and a stranger loaned me her sweater next to me. I didn’t wanna buy a blanket just for a four hour trip when I did not need the pillow or the earphones. I don’t mind purchasing a blanket, but I only needed that not all of it accessories. Cold air pretty much blew the entire trip. Two people in front of me both bought the blanket packages. Maybe that’s the idea. The crew was exceptionally nice and passed through multiple times.. the restrooms were very clean and usually accessible.
3 hour wait on customer service after flight was cancelled. Was bumped to a flight where I wouldnt have gotten to my destination for another 2 days. Had to fully refund flight and book a new one the following morning. Paid twice the amount for the flight than I had originally booked. Very disappointed I was not offered any sort of discount or points for all of the frustration, in fact the airline profited twice as much off of me by cancelling my flight and and changing my entire trip.
I understand that both Hawaiian and Alaskan are in the process of merging but I could not get real-time flight info or access my boarding pass on either app
Had a hard time checking into my flight on my phone because they gave me the wrong confirmation number. Otherwise everything else went well.
All was good and they were able to seat my travel companion next to me. Thank you.
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.
Why wasn't this flight departure scheduled eith another crew so that it could leave on time? When we arrived in Denver we had so little time between flights we had run to the connecting flight. We should received some credit for the inconvenience.
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.
| Transportation mode | Average price | Average duration |
|---|---|---|
| Flights | $798 | 2h 22m |
| Buses | $244 | 29h 33m |
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