$71 Find Cheap Flights from San Diego to Boulder - 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 San Diego to Boulder departing on 9/9. 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
$124
Typical prices: $261-$140
Frontier
Tue 8/11Tue 8/18
SAN - DEN • Non-stop
Cheapest one-way
$71
Typical prices: $77-$195
Frontier
Wed 9/9
SAN - DEN • 1 stop
Arrival airport
You can't fly directly to Boulder. It is served by Denver (DEN), located 33.4 miles from Boulder.
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Flight Deals
Useful Info
Flight Deals

Cheap Flights from San Diego to Boulder (SAN-DEN)

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from San Diego to Boulder 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 San Diego to Boulder

Tue, Aug 11 - Tue, Aug 18
Frontier Logo
6:25 am - 10:03 am
SAN
-
DEN
2h 38mnonstop
Frontier Logo
7:13 am - 8:42 am
DEN
-
SAN
2h 29mnonstop
$124Frontier
Thu, Oct 8 - Sun, Oct 11
Frontier Logo
8:32 pm - 12:06 am
SAN
-
DEN
2h 34mnonstop
Frontier Logo
10:32 pm - 11:59 pm
DEN
-
SAN
2h 27mnonstop
$126Frontier
Sun, Aug 9 - Wed, Aug 12
Frontier Logo
6:25 am - 10:03 am
SAN
-
DEN
2h 38mnonstop
Frontier Logo
7:45 am - 9:10 am
DEN
-
SAN
2h 25mnonstop
$129Frontier
Tue, Jul 28 - Tue, Aug 4
Frontier Logo
6:25 am - 10:03 am
SAN
-
DEN
2h 38mnonstop
Frontier Logo
7:40 am - 9:05 am
DEN
-
SAN
2h 25mnonstop
$131Frontier
Fri, Aug 21 - Sun, Aug 23
Frontier Logo
9:37 am - 1:13 pm
SAN
-
DEN
2h 36mnonstop
Frontier Logo
7:13 am - 8:42 am
DEN
-
SAN
2h 29mnonstop
$132Frontier
Fri, Aug 21 - Mon, Aug 24
Frontier Logo
6:25 am - 10:06 am
SAN
-
DEN
2h 41mnonstop
Frontier Logo
7:13 am - 8:42 am
DEN
-
SAN
2h 29mnonstop
$134Frontier
Tue, Aug 11 - Tue, Aug 18
Frontier Logo
4:28 pm - 2:13 pm
SAN
-
DEN
20h 45m
1 stop
Frontier Logo
7:13 am - 8:42 am
DEN
-
SAN
2h 29mnonstop
$136Frontier
Sun, Aug 9 - Mon, Aug 10
Frontier Logo
6:25 am - 10:03 am
SAN
-
DEN
2h 38mnonstop
Frontier Logo
7:45 am - 9:10 am
DEN
-
SAN
2h 25mnonstop
$137Frontier
Thu, Aug 6 - Fri, Aug 7
Frontier Logo
6:25 am - 10:03 am
SAN
-
DEN
2h 38mnonstop
Frontier Logo
10:29 pm - 11:51 pm
DEN
-
SAN
2h 22mnonstop
$138Frontier
Tue, Jul 7 - Wed, Aug 5
Frontier Logo
10:00 am - 1:41 pm
SAN
-
DEN
2h 41mnonstop
Frontier Logo
10:29 pm - 11:51 pm
DEN
-
SAN
2h 22mnonstop
$139Frontier
Useful Info

Good to know

Low seasonJanuary
Cheapest flight$71
Best time to beat the crowds with an average 20% drop in price.
Most popular time to fly with an average 21% increase in price.
Flight from San Diego to Denver

When to book flights from San Diego to Boulder

Are your dates flexible? Find out the best times to travel from San Diego to Boulder based on our flight data from the last year. Discover the cheapest month and even day to fly.
Estimated round-trip price

FAQs for booking flights from San Diego to Boulder

  • Which airports will I be using when flying from San Diego to Boulder?

    When flying out of San Diego you’ll be using San Diego. Boulder does not have its own airport so you’ll be flying into nearby Denver Intl airport, which is 33.4 mi away.

  • How long does a flight from San Diego to Boulder take?

    Direct flights cover the 852 miles separating San Diego and Boulder in about 2h 20m.

  • How many flights are there between San Diego and Boulder?

    30 direct flights run between San Diego and Boulder on a daily basis. On average, there are about 215 departures each week.

  • What’s the cheapest day of the week to fly between San Diego and Boulder?

    Consider leaving on a Friday and avoid Mondays if you are looking for the best rates. For your return to San Diego, you’ll find the best rates on Saturdays and the most expensive ones on Sundays.

  • How does KAYAK find such low prices on flights from San Diego to Boulder?

    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 San Diego to Boulder.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from San Diego to Boulder?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to Boulder from San Diego 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 San Diego to Boulder?

    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 Boulder with an airline and back to San Diego with another airline.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from San Diego to Boulder?

    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 Boulder from San Diego up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

  • Which airlines provide the cheapest flights from San Diego to Boulder?

    In the last 5 days, the cheapest one-way ticket between San Diego and Boulder found on KAYAK was with Frontier for $28. Frontier offered a round-trip connection from $49 and Hawaiian Airlines from $68.

Top tips for finding cheap flights from San Diego to Boulder

  • There is no airport in Boulder. Instead, you’ll be flying into Denver Airport when flying between San Diego and Boulder.
  • The cheapest flight from San Diego to Boulder was found 63 days before departure, on average.
  • Book at least 2 weeks before departure in order to get a below-average price.
  • High season is considered to be May, June and July. The cheapest month to fly is February.

Reviews of the top 5 airlines serving San Diego to Boulder

 
Need help choosing which airline to fly with from San Diego to Boulder? 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.
7.9
Alaska AirlinesOverall score based on 12517 reviews
7.0Entertainment
7.1Food
8.5Crew
7.8Comfort
8.1Boarding
Airline reviews

Short trip, was nice to have a drink on the short flight still.

10.0 ExcellentAnonymous, Jun 2026
SAN - MFR
Read more Alaska Airlines reviews

Short trip, was nice to have a drink on the short flight still.

Flight got delayed like 5 times, then they put and ada passenger in the back of the plane.

Flight delayed no communication. The gate was changed so many times.

Alaska is by far the best airline to fly with 😍

More efficient with checking lines and boarding/checking bags when needed.

They were really helpful with every question and my kids had never been on a plane and the staff made them feel comfortable

I was on flight #3022 departed from San Diego, California to Medford, Oregon. I had Denise & Damaris as my flight attendants. I didn’t have much interaction with Damaris, but I did with Denise who had, this calm, cool collective voice when she spoke about the emergency exit plans before takeoff. I travel often and I’ve never met a flight attendant that can put you at ease. I felt she respects and takes pride in her position and more airlines need to adopt the integrity and respect that she has for Alaska Airlines. Debbie

All airlines should board planes back to front, instead of catering to higher priced tickets. The boarding groups are inefficient and delay takeoff time

Luggage was severely damaged. Flight was late for several hours

The ticketing counter in SD was a mess. The lady handling the First-Class check-in seemed overwhelmed until a supervisor replaced her. It took almost 20 minutes to get once couple checked in, and then she started walking around the counters while 7 people just stood in line. Once her supervisor arrived, she announced she was going on break, never to engage with customers again.

Airline is not very senior friendly. Flights are late, forcing us to run to the connecting flight. Food is awful. Wish they would go back to pretzels and peanuts. During flight, pressurization isn’t quite right and all of our ears get plugged. Everything is nickel and dime, charging for boarding, seat selection and legroom. While a screen at the desk in the gate area says check your roll on bag now for free due to space limitation, the employee at the desk will not check the bag without a $100 fee. Insane.

Was fine, delayed and feels like southwest is always late

The entire experience from boarding to landing was amazing! The crew were very friendly. Will definitely be back.

Delayed flight, lack of information, boarding process is a mess as is the carryon luggage causing issues when leaving the plane….just a poor experience.

Comfortable. Easy. No problems. Just wish they had gf options for snacks.

The crew was very kind and made going to Hawaii relaxing and fun to look forward to! Thank you Southwest for a pleasant flight!

We waited in the airplane for over 45 min for a southwest employee to make the flight. This cause over half the plane to miss their connecting flight in Denver. When we confronted the desk upon arrival, they told us the only flight they had was the next day leaving at 8:50 pm!!! Or they offered to get us to Burbank or LA, but after that we were on our own to get back to Santa Barbara. I paid for a flight from sba to bna bna to sba. My re entry into mom mode has been 💯 rough because of southwest mistake with my flight. And now I’m leaving to Reno tomorrow for a vballl tournament and just discovered that my leg in Vegas has me and my 3 kids on a stand by flight even though I had booked these ticket last year November!! Do better southwest!

Terrible. Even though there’s assigned seating now, they are still the slowest boarding airline of anyone.

It was good from LAX to Phoenix, But the connection in Phoenix to Tulsa was not that great. The staff on both flights were great. The choice of free entertainment was ok nothing to brag about. The 45 min delay because of some electrical issue wasn't great from Phoenix to Tulsa. We sat there with hardly any air, The seat I had was between windows so the side of the plane pushed in on you. My being a bigger man it then made the seating area uncomfortable. The seats on the plane had no power to connect to recharge your phone or anything. I would recommend that they should look into a slot or clamp to hold your phone to enjoy while watching the entertainment choices hands-free. Also make it possible to raise the inner seat by the window be able to raise the arm rest up to make more room for larger people to set more comfortably. I would also say other then that stop price gouging the airfare or nickel and diming everything. Not fair for people having to fly for emergencies and be paying for higher prices due to the season or holidays. Your making your money either way and the cost of flying is still going to be the same regardless if there's 100 people or 200 people.

Southwest was greaat! The most expensive but the least upsetting for those we were flying to see.

Fabulous if you have a portable wheelchair. They can store it in the galley and you can just walk out with it. Really nice and the flat seats are just incredible, very nice. iPads for movies, also pretty nice,

No charging outlets worked. Other than collecting trash attendants didn’t come around. No one could hear flight attendants announcements during the flight. Seat pads were horrible. Sitting on a board for 5 hours. What happened to Hawaiian airlines comfort, hospitality, and extras? Our pilots did an excellent job trying to minimize turbulence and incredible job in landing in windy conditions.

I like that if they asked you to checked in a bag at the gate they give you priority to board

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.

The entertainment is a bit limited, it would be better if they added some games to play besides the movies and tv shows. But the seats are comfortable and the crew is polite

Food was great. Staff was phenomenal. Seats were a bit hard and could use a lot more entertainment options as far as movies to choose from. WiFi was good. Overall great trip.

Service was professional and quick. Premium economy seat was comfortable given the class

The staff was extremely helpful and friendly at all times! They went above and beyond to get us into an earlier flight in San Diego to make our connection in SFO possible, because our original flight did actually not make it! I did so much appreciate the UA team and how they made this possible. We also didn’t have seats together on the long flight to Singapore, but they found us seats together last moment with no additional cost! Nobody sat next to us, so that we were able to sleep! Thanks to UA for improving their service and Underpricer for booking this trip! Please be careful: 1,5 hrs for transfer in San Francisco might not be enough time in the future

Over 2.5 hour maintenance delay on first morning flight with no acknowledgement, compensation or even gesture of good will. Aircraft had overnighted at airport so issue should have been addressed prior to boarding. Over 3.5 hours before first slow and deliberate beverage service.

Read the fine print. This was my flight home. I booked my flight for the quickest way home. Had a carry-on and a personal item. Same as my outbound flight. Apparently I needed to pre-pay extra for my carry-on. When I checked in, I was told that I had to check it. I said I’ll pay for it, and was told that this wasn’t an option anymore. They said I still had to pay $50 to check my carry-on. I told them I’ll pay whatever to just carry it in as intended. I was not allowed, so eventually I paid $50 to check my carry-on under a plane that was half full, with overhead compartments that were even less full. My white carry-on suitcase was practically destroyed getting from Idaho falls to Denver to Orange County. The low price air fair was a bait and switch. Got me to the gate, made me pay extra, then didn’t even allow me to pay for a carry on. Not to mention that I paid the $8 for WiFi that didn’t work. All to get my suitcase destroyed. I don’t think I’m going to even keep my Untied mileage plus membership and card. Apparently, membership does not have its privileges for this one.

I flew from Santa Fe to Denver to catch a flight to London and the transfer of my luggage on arrival at Denver to the London flight worked perfectly. The crew on the ground and on board for the London flight were so friendly and efficient.

It was a short flight so I was expecting too much

Late- that’s what United does best. Missed my connection, rebooked to a flight 17 hours later and had to spend $500 on a hotel. What did I get? A $15 meal voucher. What can you get in an airport for $15. I hate United so much.

It was good overall except from Omaha to Denver when flight a was a repeatedly delayed apparently due to some issue at Denver. Communications could have been handled better. I had to board then deboard with luggage and board again

There weren't enough employees at check in took awhile to get bags checked. There wasn't a wheel chair for me, I was sent to someone who turns out to work for a different airline, if My flight hadn't been delayed I probably would have missed my flight as it was, by the time I arrived at my gate, they started boarding in about 15 minutes. I don't know who took me to my gate, definitely was not the normal people who take passengers to the gate. I'm guessing she may have been in a management position. I wish I knew her name, she went beyond to help me. With that said everyone was kind, and were doing the best they could. So, I choose to say it was an Adventure, stressful start, but good. In the end went well. The situation was not only difficult for passengers but the employee's.

Frontier scheduled a 40 minute connection in DEN. What they failed to mention was that they “close the doors” 20 mins prior to departure, which means you only have 20 mins. Not enough time. Possibly against DOT regulations. Filing complaint.

It was an early flight and most people napped/slept and the crew let us which was nice.

More inflight connection. And leg space is horrible. And the paying for baggage I'd ridiculous!!!

It was costly and difficult to check in. $85 to take a small suitcase with me, carry on or checked and $75 on the return trip, Plus $25 if I didn't check my self in check in $25, because I couldn't do it on the kiosk. Small very uncomfortable seats, waited on the runway for near an hour each way. It was my worst flight to date.

Due to weather, my flight was delayed, further delayed, then canceled. I eventually got through to a support person who helped me find a different route out of MSP, but to get to DIA, they didn't want to, but eventually did help with the connection ticket purchase. But even this replacement flight was delayed time and time again, and I would have missed my connecting flights and I didn't want to get stuck in a layover city, so after 12 hours at the airport with two young boys who were very tired, we just cancelled our plans and spent the week at home, instead of Nana's.

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.

Everything you need to know for your flight from San Diego to Boulder

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