$91+ Cheap flights from San Diego (SAN) to Boulder, CO
This is the cheapest round-trip flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 12/13. Fares are subject to change and may not be available on all flights or dates of travel.
SAN — DEN
Oct 15 — Oct 221
Round-trip
1 adult, Economy
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Find cheap flights from San Diego to Boulder with Cheapflights
1. Tell us where you want to go
Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”2. Select your favorite providers
We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.3. Compare prices and book
Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.Cheapflights Tip: The best prices from San Diego to Boulder are usually found in February or January, booked 63 days in advance, depart on a Friday or Saturday and return on a Thursday
Cheap flight deals from San Diego to Boulder
Cheapest
Best
Last-minute
One-way
Cheapest flights from San Diego to BoulderExplore the most affordable flight options available from San Diego to Boulder. Find the lowest fares from popular airlines and budget airlines, with prices last updated on September 15, 2026.
Explore the most affordable flight options available from San Diego to Boulder. Find the lowest fares from popular airlines and budget airlines, with prices last updated on September 15, 2026.
This Cheapflightsfares deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/204:53 pm -
Nonstop2h 31m
Tue 10/2710:29 pm -
1 stop21h 09m
Deal found 9/10![Frontier logo]()
$100
This Cheapflightsfares deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 11/136:25 am -
Nonstop2h 34m
Mon 11/167:00 am -
1 stop4h 11m
Deal found 9/10![Frontier logo]()
$101
This Cheapflightsfares deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/24:54 pm -
Nonstop2h 28m
Tue 10/610:29 pm -
Nonstop2h 22m
Deal found 9/10![Frontier logo]()
$102
This Priceline deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 11/134:53 pm -
Nonstop2h 32m
Tue 11/177:00 am -
1 stop4h 11m
Deal found 9/11![Frontier logo]()
$103
This Frontier deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 11/236:30 am -
Nonstop2h 34m
Wed 12/22:20 pm -
Nonstop2h 26m
Deal found 9/14![Frontier logo]()
$104
This Cheapflightsfares deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/296:25 am -
Nonstop2h 34m
Sat 10/319:21 am -
1 stop10h 17m
Deal found 9/11![Frontier logo]()
$105
This Cheapflightsfares deal was found by Cheapflights users on 9/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 11/64:53 pm -
Nonstop2h 32m
Sun 11/82:38 pm -
Nonstop2h 30m
Deal found 9/13![Frontier logo]()
$106
This Super.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/276:25 am -
Nonstop2h 34m
Sat 10/312:28 pm -
Nonstop2h 30m
Deal found 9/11![Frontier logo]()
$107
This Cheapflightsfares deal was found by Cheapflights users on 9/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/104:53 pm -
Nonstop2h 31m
Mon 10/1210:29 pm -
Nonstop2h 27m
Deal found 9/13![Frontier logo]()
$109
This Super.com deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/64:54 pm -
Nonstop2h 28m
Tue 10/1310:29 pm -
Nonstop2h 27m
Deal found 9/14![Frontier logo]()
$110
This Super.com deal was found by Cheapflights users on 9/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/214:53 pm -
Nonstop2h 31m
Sat 10/242:29 pm -
Nonstop2h 29m
Deal found 9/15![Frontier logo]()
$111
This Kiwi.com deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 11/226:30 am -
Nonstop2h 34m
Wed 12/22:20 pm -
Nonstop2h 26m
Deal found 9/14![Frontier logo]()
$112
Best flights from San Diego to BoulderDiscover carefully curated flight deals from San Diego to Boulder that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated September 15, 2026.
Discover carefully curated flight deals from San Diego to Boulder that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated September 15, 2026.
This Southwest deal was found by Cheapflights users on 9/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/204:40 pm -
1 stop4h 15m
Sat 10/248:45 am -
1 stop4h 35m
Deal found 9/13![Southwest logo]()
$212
This Delta deal was found by Cheapflights users on 9/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 11/111:31 pm -
1 stop5h 58m
Sun 11/155:35 am -
1 stop4h 13m
Deal found 9/13![Delta logo]()
$227
This United Airlines deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals ”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/236:45 am -
Nonstop2h 31m
Sun 12/279:01 pm -
Nonstop2h 31m
Deal found 9/10![United Airlines logo]()
$270
This Alaska Airlines deal was found by Cheapflights users on 9/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 2/113:15 pm -
Nonstop2h 18m
Mon 2/158:20 am -
Nonstop2h 25m
Deal found 9/12![Alaska Airlines logo]()
$287
This Southwest deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/99:15 pm -
Nonstop2h 30m
Mon 10/128:50 pm -
1 stop4h 20m
Deal found 9/14![Southwest logo]()
$243
This Southwest deal was found by Cheapflights users on 9/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 12/126:50 am -
1 stop4h 45m
Thu 12/243:45 pm -
1 stop4h 10m
Deal found 9/12![Southwest logo]()
$243
This United Airlines deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/1012:37 pm -
1 stop6h 23m
Sat 11/1411:20 am -
1 stop8h 17m
Deal found 9/14![United Airlines logo]()
$292
This Delta deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/2410:57 am -
1 stop6h 12m
Sun 10/255:25 am -
1 stop8h 00m
Deal found 9/14![Delta logo]()
$297
This United Airlines deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 11/1112:37 pm -
1 stop6h 23m
Tue 11/1711:20 am -
1 stop8h 17m
Deal found 9/14![United Airlines logo]()
$292
This Alaska Airlines deal was found by Cheapflights users on 9/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/92:33 pm -
Nonstop2h 28m
Mon 10/126:59 pm -
Nonstop2h 35m
Deal found 9/13![Alaska Airlines logo]()
$562
This Southwest deal was found by Cheapflights users on 9/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 11/211:20 pm -
2 stops5h 50m
Sat 11/285:45 am -
1 stop4h 55m
Deal found 9/13![Southwest logo]()
$498
Last-minute flights from San Diego to BoulderDiscover last-minute flight deals from San Diego to Boulder. Data last updated September 15, 2026 and is based on user searches.
Discover last-minute flight deals from San Diego to Boulder. Data last updated September 15, 2026 and is based on user searches.
This Cheapflightsfares deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/24:54 pm -
Nonstop2h 28m
Tue 10/610:29 pm -
Nonstop2h 22m
Deal found 9/10![Frontier logo]()
$102
This Super.com deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/64:54 pm -
Nonstop2h 28m
Tue 10/1310:29 pm -
Nonstop2h 27m
Deal found 9/14![Frontier logo]()
$110
This Cheapflightsfares deal was found by Cheapflights users on 9/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/104:53 pm -
Nonstop2h 31m
Mon 10/1210:29 pm -
Nonstop2h 27m
Deal found 9/13![Frontier logo]()
$109
This Cheapflightsfares deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/154:53 pm -
Nonstop2h 31m
Tue 10/202:29 pm -
Nonstop2h 29m
Deal found 9/10![Frontier logo]()
$113
This Cheapflightsfares deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/204:53 pm -
Nonstop2h 31m
Tue 10/2710:29 pm -
1 stop21h 09m
Deal found 9/10![Frontier logo]()
$100
This Priceline deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/214:53 pm -
Nonstop2h 31m
Mon 10/262:39 pm -
Nonstop2h 29m
Deal found 9/14![Frontier logo]()
$104
This Super.com deal was found by Cheapflights users on 9/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/214:53 pm -
Nonstop2h 31m
Sat 10/242:29 pm -
Nonstop2h 29m
Deal found 9/15![Frontier logo]()
$111
This Cheapflightsfares deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/264:53 pm -
Nonstop2h 31m
Tue 10/272:28 pm -
Nonstop2h 30m
Deal found 9/10![Frontier logo]()
$114
This Cheapflightsfares deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/276:25 am -
Nonstop2h 34m
Sat 10/312:28 pm -
Nonstop2h 30m
Deal found 9/10![Frontier logo]()
$106
This Cheapflightsfares deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/296:25 am -
Nonstop2h 34m
Sat 10/319:21 am -
1 stop10h 17m
Deal found 9/11![Frontier logo]()
$105
One-way flights from San Diego to BoulderSearch for one-way flight options from San Diego to Boulder. Find affordable one-way fares based on user searches. Data last updated September 15, 2026.
Search for one-way flight options from San Diego to Boulder. Find affordable one-way fares based on user searches. Data last updated September 15, 2026.
This Kiwi.com deal was found by Cheapflights users on 9/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 12/134:41 pm -
Nonstop2h 34m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/13![Frontier logo]()
$91
This Kiwi.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/127:33 pm -
1 stop15h 33m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/11![Frontier logo]()
$92
This Cheapflightsfares deal was found by Cheapflights users on 9/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/192:01 pm -
1 stop8h 42m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/10![Frontier logo]()
$94
This Kiwi.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/16:54 pm -
1 stop22h 21m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/11![Frontier logo]()
$95
This Kiwi.com deal was found by Cheapflights users on 9/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/298:32 pm -
2 stops22h 43m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/11![Frontier logo]()
$97
This Kiwi.com deal was found by Cheapflights users on 9/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/106:25 am -
Nonstop2h 33m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/12![Frontier logo]()
$100
This United Airlines deal was found by Cheapflights users on 9/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/177:00 am -
Nonstop2h 33m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/14![United Airlines logo]()
$101
This Southwest deal was found by Cheapflights users on 9/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/283:20 pm -
Nonstop2h 15m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/13![Southwest logo]()
$102
Find flight deals from San Diego to Boulder
Keep the following information in mind while searching for San Diego to Boulder flight deals. Data was last updated September 15, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $101 (Frontier) |
One-way from | $91 (Kiwi.com) |
Popular in | June |
Cheapest in | February |
Average price | $217 |
Cheapflights Fare Finder
Customize your flight search to find flights from San Diego to Boulder that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 7,457,451 searches. Data last updated September 15, 2026.
Use the filters below to find and compare flights from San Diego to Boulder that are best for you.
Fly from
Fly to
Route
Depart
Return
Cheapest round-trip
San DiegoDenver
SAN San Diego - DEN Denver Intl
SANDEN
San Diego
Mon 11/9
8:00 pm-11:20 pm
Nonstop2h 20m
Denver Intl
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$109
San DiegoDenver
SAN San Diego - DEN Denver Intl
SANDEN
San Diego
Fri 10/23
12:45 pm-5:45 pm
1 stop4h 00m
Denver Intl
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$114
San DiegoDenver
SAN San Diego - DEN Denver Intl
SANDEN
San Diego
Wed 3/10
3:59 pm-11:00 pm
1 stop6h 01m
Denver Intl
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$119
San DiegoDenver
SAN San Diego - DEN Denver Intl
SANDEN
San Diego
Wed 10/14
3:59 pm-11:53 pm
1 stop6h 54m
Denver Intl
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$119
San DiegoDenver
SAN San Diego - DEN Denver Intl
SANDEN
San Diego
Wed 11/11
1:31 pm-8:29 pm
1 stop5h 58m
Denver Intl
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$119
San DiegoDenver
SAN San Diego - DEN Denver Intl
SANDEN
San Diego
Thu 12/17
3:00 pm-8:05 pm
1 stop4h 05m
Denver Intl
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$121
San DiegoDenver
SAN San Diego - DEN Denver Intl
SANDEN
San Diego
Mon 3/8
3:59 pm-11:00 pm
1 stop6h 01m
Denver Intl
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$129
San DiegoDenver
SAN San Diego - DEN Denver Intl
SANDEN
San Diego
Mon 10/12
8:00 am-11:32 am
Nonstop2h 32m
Denver Intl
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$134
San DiegoDenver
SAN San Diego - DEN Denver Intl
SANDEN
San Diego
Mon 10/12
9:15 pm-12:45 am
Nonstop2h 30m
Denver Intl
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$134
Quickest round-trip
San DiegoDenver
SAN San Diego - DEN Denver Intl
SANDEN
San Diego
Thu 3/11
8:15 am-11:34 am
Nonstop2h 19m
Denver Intl
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$144
Showing 1-10 of 21 resultsSorted by cheapest first
Best time to book a flight from San Diego to Boulder
Have a flexible travel schedule? Discover the best time to fly to Boulder from San Diego with our price prediction graph.
SAN-DEN
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.
Cheapflights Insights
Everything you need to know about your flight from San Diego to Boulder
SAN-BD9
SAN-DEN
What is the cheapest time of day to fly from SAN to BD9?
Find hourly flight availability from San Diego to Boulder. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated September 15, 2026.
A simple way to save on the total cost of your ticket is to fly from San Diego to Boulder in the evening. If you’re flexible enough to do this you can expect to save up to 35% on your trip compared to booking a flight in the morning.
Weekly flight availability from San Diego to Boulder
Explore weekly flight availability from San Diego to Boulder. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated September 15, 2026.
The most flights from SAN to BD9 are scheduled on a Monday (31 on average). You will have fewer flight options on Tuesday, which is when the least amount of flights are scheduled (11 on average).
How much does it cost to fly round-trip from San Diego to Boulder?
Airfare is below average for this route at the moment.
San Diego to Boulder flights typically cost between $145 and $294 in November.The cheapest round-trip price found within the last 5 days was $101 on Frontier (Nov 12-Nov 14).
What is the cheapest day to fly from San Diego to Boulder?
Use this chart to determine the cheapest time to fly round-trip from San Diego to Boulder. Price data was last updated on September 12, 2026.
Travelers seeking maximum savings on their San Diego to Boulder flight should consider departing on Tuesday evenings when fares are most often at their lowest. Monday afternoons flights should be avoided if possible as fares are typically the most expensive at this time.
Reviews of airlines servicing Boulder
Get insights into the airlines that provide service to Boulder. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Boulder. Reviews last updated September 15, 2026.
See what other customers who have flown with Southwest,Alaska Airlines, andUnited Airlines from San Diego to Boulder have to say. You can also see how each airline compares in terms of entertainment options, comfort, food, crew/service, and boarding process.
Boarding
8.1
Overall
8.0
Comfort
8.0
Food
7.0
Crew
8.6
Entertainment
7.5
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Boarding
8.1
Overall
8.0
Comfort
8.0
Food
7.0
Crew
8.6
Entertainment
7.5
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Boarding
8.1
Overall
8.0
Comfort
8.0
Food
7.0
Crew
8.6
Entertainment
7.5
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Boarding
8.1
Overall
8.0
Comfort
8.0
Food
7.0
Crew
8.6
Entertainment
7.5
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Boarding
8.1
Overall
8.0
Comfort
8.0
Food
7.0
Crew
8.6
Entertainment
7.5
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
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| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$46 | Average$143 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$116 | Average$210 | FlexibilityNo cancel fee | On-time75% | |
| Cheapest$117 | Average$306 | FlexibilityNo cancel fee | On-time63% | |
| Cheapest$117 | Average$314 | FlexibilityNo cancel fee | On-time69% |