$43 Find Cheap Flights from San Diego to Boulder

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 6/3. 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.
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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

Wed, Jun 4 - Sat, Jun 7
Frontier Logo
6:35 am - 10:10 amSAN-DEN
2h 35mnonstop
Frontier Logo
10:29 pm - 11:55 pmDEN-SAN
2h 26mnonstop
$97Frontier
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Tue, May 27 - Sat, May 31
Frontier Logo
6:50 am - 10:21 amSAN-DEN
2h 31mnonstop
Frontier Logo
3:48 pm - 5:20 pmDEN-SAN
2h 32mnonstop
$98Frontier
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Wed, Jun 4 - Sat, Jun 7
American Airlines Logo
4:31 pm - 10:40 pmSAN-DEN
5h 09m1 stop
American Airlines Logo
12:14 pm - 3:24 pmDEN-SAN
4h 10m1 stop
$159American Airlines
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Sun, Jul 13 - Tue, Jul 15
United Airlines Logo
6:45 am - 10:13 amSAN-DEN
2h 28mnonstop
United Airlines Logo
4:00 pm - 8:50 pmDEN-SAN
5h 50m1 stop
$161United Airlines
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Sat, Aug 23 - Thu, Aug 28
American Airlines Logo
4:20 pm - 10:07 pmSAN-DEN
4h 47m1 stop
American Airlines Logo
12:14 pm - 3:25 pmDEN-SAN
4h 11m1 stop
$163American Airlines
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Mon, Jun 16 - Wed, Jun 18
United Airlines Logo
11:15 am - 6:05 pmSAN-DEN
5h 50m1 stop
United Airlines Logo
7:50 pm - 9:14 pmDEN-SAN
2h 24mnonstop
$165United Airlines
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Sat, May 17 - Mon, May 19
Southwest Logo
9:30 am - 12:50 pmSAN-DEN
2h 20mnonstop
Southwest Logo
6:50 am - 8:15 amDEN-SAN
2h 25mnonstop
$197Southwest
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Tue, Jul 8 - Fri, Jul 11
Southwest Logo
9:40 am - 3:50 pmSAN-DEN
5h 10m1 stop
Southwest Logo
7:00 am - 8:20 amDEN-SAN
2h 20mnonstop
$211Southwest
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Sat, Jun 21 - Fri, Jun 27
Delta Logo
5:04 pm - 11:48 pmSAN-DEN
5h 44m1 stop
Delta Logo
7:21 pm - 10:53 pmDEN-SAN
4h 32m1 stop
$217Delta
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Wed, Jun 18 - Fri, Jun 20
Delta Logo
4:02 pm - 11:48 pmSAN-DEN
6h 46m1 stop
Delta Logo
6:23 pm - 11:44 pmDEN-SAN
6h 21m1 stop
$227Delta
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Good to know

Low seasonJanuary
High seasonAugust
Cheapest flight$43
Best time to beat the crowds with an average 21% drop in price.
Most popular time to fly and prices are also 4% lower on average.
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?

    34 direct flights run between San Diego and Boulder on a daily basis. On average, there are about 238 departures each week.

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

    Consider leaving on a Wednesday and avoid Thursdays if you are looking for the best rates. For your return to San Diego, you’ll find the best rates on Wednesdays and the most expensive ones on Fridays.

  • 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 72 hours, the cheapest one-way ticket between San Diego and Boulder found on KAYAK was with Frontier for $43. Frontier offered a round-trip connection from $97 and American Airlines from $159.

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 44 days before departure, on average.
  • Book at least 1 week before departure in order to get a below-average price.
  • High season is considered to be February, March and April. The cheapest month to fly is January.

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.
8.0
SouthwestOverall score based on 4292 reviews
8.2Boarding
8.0Comfort
7.6Entertainment
8.6Crew
7.1Food
Airline reviews

After a 3 hour layover in Denver my flight was delayed over 5 hours! No explanation; no assistance; no offer to provide compensation; no one at Southwest was willing to offer any assistance. 8 hours in the Denver airport - ridiculous!

2.0 MediocreAnonymous, Apr 2025MSY - DEN
Read more Southwest reviews

After a 3 hour layover in Denver my flight was delayed over 5 hours! No explanation; no assistance; no offer to provide compensation; no one at Southwest was willing to offer any assistance. 8 hours in the Denver airport - ridiculous!

It was a perfect flight in all aspects! Both legs!

Great flight, 47 passengers on a 180 seat plane. Stewardess was pleasant and cheerful.

I liked the crew member who gave flight instructions on "in case of a problem:. The seats are so small that only a young teenager could sit in middle seat.

WiFi on the flight was not working. Thus, entertainment options were limited.

Great flight staff. Ease of boarding. Overall, very uneventful and easy trip.

I really like open seating. I hate that I've heard this is going away. This is one of the unique things that makes Southwest my goto choice.

Employees were kind and funny, as always! Flight was late but no announcements were made for people with tight connections to help them transition quickly. No service due to turbulence.

I recently flew Southwest from San Jose to Honolulu. I was very impressed with the flight crew, especially the flight attendant in charge of the front of the plane. She came through the aisle at least five times for drinks and water, and two times for snacks. I have not seen such service since I flew first class. Also, for the first time, they gave us the correct baggage claim number, and the luggage came out quickly. I can't wait for Southwest to have assigned seating! I absolutely hate the Cattle Call boarding procedure and the mad dash to get seats and overhead bins. However, the boarding was efficient.

For the first time in a long time we had a flawless experience with Southwest. Both flights were early and no mechanical errors at all. We were shocked and pleasantly surprised 😮.

737-800 in first class was pretty dumpy. Seat had an uncomfortable angle, storage under the seat was blocked so even my very modest backpack didn't fit, power outlet was flaky. Weird tiny seat pockets that couldn't hold a gallon ziploc bag, emesis bag missing, etc. etc. No in-flight service due to turbulence. Crew was excellent, boarding was smooth despite a full flight.

Delta flight was on time, seats were comfortable, and crew was nice.

Thank you for not flipping the plane on the run way. You guys get a 5 star rating for the flight!!!

Boarding is, as it always is… horrible. Gate lice. Slow moving zones. Too many people with carry ons

It was terrible, if they ran flights on time it would make a big difference.

Delta seems to be improving in many areas, except they are super bad with the food available. Bring back normal food service on long flights.

Airline lost my luggage and set me back a day worth of travel due to having to stay in Denver to wait on my luggage

I actually received a notification from kayak on email but not one by text from Delta when my departure gait changed and I almost missed my flight

New boarding doesn't make sense. Filling front first is slow.

Delta flight was great from the check in all the way to arrival. However, I had a very bad experience. I requested a wheelchair and the wheelchair employee that went to pick me up from the plane in Boston to bring me to the baggage claims told me I have to pay him. I was under the impression that it was a free service and I usually give tips but the person forced me to pay and since I said no because I was upset with his demand when my daughter walked in to pick me up he demanded payment from my daughter who paid him thinking maybe now it is a charged service.

The gate attendant let me walk right by her with a bag too big for the overhead compartment

Food choices were very limited. Taste of the dishes was average.

I liked all the informational texts. I always knew where to go and when .

Received an email the night before showing that there would be seatback entertainment on our flight. We get on and there was no seatback entertainment. And then it was a scramble to try to set up the iPads for the kids before takeoff so they could watch something for the four hour flight.

The reason I don’t fly United. No in seat entertainment for a long flight and inconsistent WiFi and entertainment available from my device.

It was a good flight. Nothing comes to mind about how it could have been better. It was a newer plane, seemed like a great upgrade from your older ones. Staff was very good as well.

The food for long haul was poor compared to Singapore airlines economy. Pasta plain with tomato sauce . Singapore airlines give me Hagen dash small ice cream cup it was great. The choices of dinner course Singapore air also much better The crew mostly friendly. The economy seat are as expected.

The plane was clean. The staff was excellent. The flight attendants were very good. Enjoyable flight. Overall. The seats in the back are too small but, will always be.

Flight was 3 1/2 hour delayed with no credit or meal vouchers

late departure due to some unspecified issue with ventilating the cabin. They got it running but it was FREEZING for the whole flight. I asked for a blanket but they didn't provide one. They could not turn up the heat. it was quite miserable.

Very helpful ground crew after an earlier flight delay and being rebooked on a different flight.

Terrible. The flight was delayed two hours due to weather. Then when we got on the plane, the first pilot ended up timing out and we had to wait for a second pilot. Second pile came on board and we tax it out. Had to return back to the gate because of an unruly passenger. Then the copilot timed out. Had to wait for new copilot. Also had to wait for maintenance to check for fuel. Then found out the second pilot timed out and we had to wait for a third pilot. Was ready to go and then needed maintenance again for another issue. In the end, it was 2 o’clock in the morning when they announced that the flight couldn’t go because the third pilot and the second copilot had timed out.

The plane was late and then sat on the runway for almost 45 minutes before taking off.

We kept being told that the flight was full and that all overhead compartments were full and therefore had to check in our hand luggage. We were some of the last people to board and noticed that there was still sufficient space in the overhead compartments. We were obliged to check in hand luggage when there was space and so had to wait at luggage retrieval which took a while to then noticed damage to our luggage - not a great experience!

This was an overnight flight. There was no meal service in first class, just a simple snack basket was offered along with beverages. There should have been some type of continental breakfast prior to arrival in PHL. As an Executive Platinum American Airlines Advantage member, I received no name recognition from the first class flight attendant. When disembarking at PHL, the flight attendants were more interested in their cell phones than saying "thank you" to the passengers as they disembarked.

The flight was quick and to the point. The crew just did their job w/o excessive talking and everything was just perfect.

Awkward carry on process. Forced to check all carry on. No overhead space of worthiness. Left delayed, but made up the time. Crew was amicable.

One of the best flights I’ve had. So smooth.

Amazingly comfy flight - I had upgraded for a reasonable price and it was worth it. The food also was good.

Had to wait on pilot and crew to depart and had to wait to arrive at the gate because they only had 2 crews working. Delays, delays....Planes just keep getting smaller and tighter and they nickle and dime for everything. When will an airline actually wake up and make flying more enjoyable?

Seats are uncomfortable but price is good. Guess I can put up with misery for four hours.

The plane failed preflight inspection, so we sat there for 90 mins while they tried to fix it. Ultimately, everything was remedied and we made our connecting flight; instead of a 2 hour layover at the airport, we spent it waiting on the plane.

I loked walking out on the tarmac to board and no first class. I didn't like that they have no snacks or onboard wifi to bide your time.

The seats were extremely hard and uncomfortable. It was disappointing even for a budget airline.

Delayed each time on a round trip with no significant weather interference. Updates to flight times came after the fact. 30 min behind in boarding and board and phone still show an on time departure. Some mysterious extra 300 miles that came so surprising they had to fuel while we were already on board?

We had an awful experience getting our bags checked in. Frontier’s check in on the app manipulated us into buying the business package because that was the only option available for a checked bag which included two checked bags per person which we did not need. Upon arriving to the airport, we stood in line for what seemed like forever at the baggage check in and there was no one available at the counter. We were first in line and we were afraid we were going to miss our flight due to the baggage attendant being late. After realizing there were a lot of other people waiting at the baggage check in and no one available. I reached out to Frontier and could not get any customer service so I had to call the airport to page the baggage attendant to send someone to the counter to check in our bags before we were able to go through security , I finally spoke to the attendant at the counter and explained to her that we had to pay for two checked bags person a total of six bags when we only had a total of three bags between three people she said to reach out to Frontier and they would issue a refund for the three bags that we paid for and did not need. I reached out to Frontier which I was not able to reach anybody by phone so I had to go through their automated chat feature, which sent me around in circles until I finally reached a representative to assist me. I explained to them what happened and they explained that they were not able to assist me. I continued to push the issue with them as this was very frustrating and they finally put in a customer service ticket where we were issued a flight credit and we were so disappointed because after this experience, we NEVER want to fly Frontier again, and we do not want a credit that we will not use. Frontier charged us almost $500 for us to check three bags which is absolutely absurd! The customer service agents were not able to offer anything else other than a flight credit and I do not feel like my frustrations were truly heard , we will never use Frontier Airlines again ! Truly Theft by Manipulation! They should be ashamed!

Our flight was canceled for no known reason. We weren’t told until we were checking in at 5:00 am. This was after our last flight with Frontier where we sat on the plane for three hours (not an exaggeration) before we took off because of a mechanical issue. We won’t be flying Frontier again.

Allowed me to chose my seat without extra charge (I purchased full-price ticket) and boarding was in group1. Didn't even serve water.

Stuck in Phoenix for two days, not even a hotel voucher offered.

Every day about it was very different all the boarding pass where all wrong l miss flight no refund all crazy

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