$88+ Cheap flights from San Diego (SAN) to Boulder, CO
This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 9/29. Fares are subject to change and may not be available on all flights or dates of travel.
SAN — DEN
Sep 5 — Sep 121
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 August 6, 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 August 6, 2026.
This Frontier deal was found by Cheapflights users on 8/6. 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.
Sat 9/194:54 pm -
Nonstop2h 28m
Sun 9/2010:29 pm -
Nonstop2h 22m
Deal found 8/6![Frontier logo]()
$123
This Kiwi.com deal was found by Cheapflights users on 8/4. 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 8/276:25 am -
Nonstop2h 38m
Tue 9/12:45 pm -
1 stop6h 30m
Deal found 8/4![Frontier logo]()
$128
This Kiwi.com deal was found by Cheapflights users on 8/3. 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.
Fri 9/184:54 pm -
Nonstop2h 28m
Wed 9/237:00 am -
1 stop6h 53m
Deal found 8/3![Frontier logo]()
$129
This Kiwi.com deal was found by Cheapflights users on 8/3. 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 10/186:25 am -
Nonstop2h 33m
Fri 10/236:10 am -
1 stop7h 30m
Deal found 8/3![Frontier logo]()
$130
This Cheapflightsfares deal was found by Cheapflights users on 8/6. 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 9/33:45 pm -
Nonstop2h 35m
Tue 9/810:29 pm -
Nonstop2h 22m
Deal found 8/6![Frontier logo]()
$131
This Kiwi.com deal was found by Cheapflights users on 8/3. 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 8/273:45 pm -
Nonstop2h 35m
Sun 8/3010:29 pm -
Nonstop2h 22m
Deal found 8/3![Frontier logo]()
$132
This Kiwi.com deal was found by Cheapflights users on 8/4. 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.
Wed 9/164:54 pm -
Nonstop2h 28m
Tue 9/2210:47 pm -
1 stop15h 06m
Deal found 8/4![Frontier logo]()
$133
This Frontier deal was found by Cheapflights users on 8/3. 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.
Sun 9/204:54 pm -
Nonstop2h 28m
Tue 9/2210:29 pm -
Nonstop2h 22m
Deal found 8/3![Frontier logo]()
$134
This Kiwi.com deal was found by Cheapflights users on 8/6. 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 11/56:25 am -
Nonstop2h 33m
Thu 11/52:12 pm -
Nonstop2h 29m
Deal found 8/6![Frontier logo]()
$135
This Cheapflightsfares deal was found by Cheapflights users on 8/4. 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 9/104:54 pm -
Nonstop2h 28m
Sun 9/1310:29 pm -
Nonstop2h 22m
Deal found 8/4![Frontier logo]()
$136
This Super.com deal was found by Cheapflights users on 8/4. 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.
Thu 10/226:25 am -
Nonstop2h 33m
Thu 10/222:12 pm -
Nonstop2h 29m
Deal found 8/4![Frontier logo]()
$137
This Expedia deal was found by Cheapflights users on 8/6. 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 Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/106:25 am -
Nonstop2h 34m
Mon 9/142:28 pm -
Nonstop2h 30m
Deal found 8/6![Frontier logo]()
$138
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 August 6, 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 August 6, 2026.
This Delta deal was found by Cheapflights users on 8/1. 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.
Thu 9/1010:54 am -
1 stop6h 17m
Sun 9/205:30 am -
1 stop4h 11m
Deal found 8/1![Delta logo]()
$197
This Southwest deal was found by Cheapflights users on 8/1. 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 8/291:55 pm -
1 stop4h 40m
Sat 9/51:35 pm -
2 stops6h 20m
Deal found 8/1![Southwest logo]()
$223
This United Airlines deal was found by Cheapflights users on 8/3. 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 12/228:45 am -
Nonstop2h 30m
Tue 12/299:01 pm -
Nonstop2h 31m
Deal found 8/3![United Airlines logo]()
$377
This Delta deal was found by Cheapflights users on 8/3. 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 9/910:54 am -
1 stop6h 17m
Mon 9/147:55 pm -
1 stop4h 52m
Deal found 8/3![Delta logo]()
$207
This Delta deal was found by Cheapflights users on 8/3. 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.
Thu 9/1010:54 am -
1 stop6h 17m
Mon 9/147:55 pm -
1 stop4h 52m
Deal found 8/3![Delta logo]()
$217
This Southwest deal was found by Cheapflights users on 8/5. 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 9/237:25 am -
1 stop4h 10m
Sat 9/261:35 pm -
2 stops6h 20m
Deal found 8/5![Southwest logo]()
$258
This Alaska Airlines deal was found by Cheapflights users on 8/2. 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 10/92:59 pm -
1 stop6h 38m
Mon 10/127:07 am -
1 stop7h 16m
Deal found 8/2![Alaska Airlines logo]()
$637
This United Airlines deal was found by Cheapflights users on 8/3. 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.
Thu 8/272:24 pm -
1 stop5h 49m
Sun 8/308:00 am -
1 stop4h 35m
Deal found 8/3![United Airlines logo]()
$397
This Alaska Airlines deal was found by Cheapflights users on 8/6. 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 8/213:51 pm -
Nonstop2h 35m
Sun 8/238:06 pm -
Nonstop2h 44m
Deal found 8/6![Alaska Airlines logo]()
$667
This Delta deal was found by Cheapflights users on 8/6. 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.
Tue 10/61:36 pm -
1 stop4h 58m
Fri 10/910:45 am -
2 stops9h 29m
Deal found 8/6![Delta logo]()
$715
This Delta deal was found by Cheapflights users on 8/5. 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 9/263:00 pm -
1 stop5h 49m
Mon 9/286:06 pm -
2 stops6h 41m
Deal found 8/5![Delta logo]()
$786
This Delta deal was found by Cheapflights users on 8/2. 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 11/113:00 pm -
2 stops7h 00m
Sun 11/155:25 am -
1 stop4h 23m
Deal found 8/2![Delta logo]()
$794
Last-minute flights from San Diego to BoulderDiscover last-minute flight deals from San Diego to Boulder. Data last updated August 6, 2026 and is based on user searches.
Discover last-minute flight deals from San Diego to Boulder. Data last updated August 6, 2026 and is based on user searches.
This Kiwi.com deal was found by Cheapflights users on 8/4. 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 8/276:25 am -
Nonstop2h 38m
Tue 9/12:45 pm -
1 stop6h 30m
Deal found 8/4![Frontier logo]()
$128
This Kiwi.com deal was found by Cheapflights users on 8/3. 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 8/273:45 pm -
Nonstop2h 35m
Sun 8/3010:29 pm -
Nonstop2h 22m
Deal found 8/3![Frontier logo]()
$132
This Booking.com deal was found by Cheapflights users on 8/3. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/278:27 pm -
Nonstop2h 29m
Sat 8/298:06 pm -
Nonstop2h 44m
Deal found 8/3![Alaska Airlines logo]()
$140
This Cheapflightsfares deal was found by Cheapflights users on 8/6. 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 9/33:45 pm -
Nonstop2h 35m
Tue 9/810:29 pm -
Nonstop2h 22m
Deal found 8/6![Frontier logo]()
$131
This Cheapflightsfares deal was found by Cheapflights users on 8/4. 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 9/104:54 pm -
Nonstop2h 28m
Sun 9/1310:29 pm -
Nonstop2h 22m
Deal found 8/4![Frontier logo]()
$136
This Expedia deal was found by Cheapflights users on 8/6. 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 Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/106:25 am -
Nonstop2h 34m
Mon 9/142:28 pm -
Nonstop2h 30m
Deal found 8/6![Frontier logo]()
$138
This Kiwi.com deal was found by Cheapflights users on 8/4. 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.
Wed 9/164:54 pm -
Nonstop2h 28m
Tue 9/2210:47 pm -
1 stop15h 06m
Deal found 8/4![Frontier logo]()
$133
This Kiwi.com deal was found by Cheapflights users on 8/3. 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.
Fri 9/184:54 pm -
Nonstop2h 28m
Wed 9/237:00 am -
1 stop6h 53m
Deal found 8/3![Frontier logo]()
$129
This Frontier deal was found by Cheapflights users on 8/6. 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.
Sat 9/194:54 pm -
Nonstop2h 28m
Sun 9/2010:29 pm -
Nonstop2h 22m
Deal found 8/6![Frontier logo]()
$123
This Kiwi.com deal was found by Cheapflights users on 8/5. 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 9/194:54 pm -
Nonstop2h 28m
Sat 9/267:00 am -
1 stop6h 53m
Deal found 8/5![Frontier logo]()
$141
This Frontier deal was found by Cheapflights users on 8/3. 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.
Sun 9/204:54 pm -
Nonstop2h 28m
Tue 9/2210:29 pm -
Nonstop2h 22m
Deal found 8/3![Frontier logo]()
$134
This Kiwi.com deal was found by Cheapflights users on 8/4. 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.
Wed 9/234:54 pm -
Nonstop2h 28m
Wed 9/307:00 am -
1 stop6h 53m
Deal found 8/4![Frontier logo]()
$142
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 August 6, 2026.
Search for one-way flight options from San Diego to Boulder. Find affordable one-way fares based on user searches. Data last updated August 6, 2026.
This Kiwi.com deal was found by Cheapflights users on 8/2. 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.
Tue 9/297:04 pm -
1 stop22h 11m
Deal found 8/2![Frontier logo]()
$88
This American Airlines deal was found by Cheapflights users on 8/2. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/274:22 pm -
1 stop4h 20m
Deal found 8/2![American Airlines logo]()
$89
This Kiwi.com deal was found by Cheapflights users on 8/4. 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.
Mon 10/57:04 pm -
1 stop13h 39m
Deal found 8/4![Frontier logo]()
$90
This Kiwi.com deal was found by Cheapflights users on 8/4. 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.
Tue 11/39:57 am -
1 stop22h 38m
Deal found 8/4![Frontier logo]()
$91
This Super.com deal was found by Cheapflights users on 8/5. 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.
Sun 9/274:54 pm -
Nonstop2h 28m
Deal found 8/5![Frontier logo]()
$92
This Kiwi.com deal was found by Cheapflights users on 8/5. 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 9/66:25 am -
2 stops17h 19m
Deal found 8/5![Frontier logo]()
$94
This Kiwi.com deal was found by Cheapflights users on 8/5. 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.
Tue 8/256:25 am -
1 stop28h 08m
Deal found 8/5![Frontier logo]()
$95
This Kiwi.com deal was found by Cheapflights users on 8/3. 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.
Fri 9/187:04 pm -
1 stop22h 11m
Deal found 8/3![Frontier logo]()
$96
This Kiwi.com deal was found by Cheapflights users on 8/3. 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 10/319:57 am -
1 stop23h 38m
Deal found 8/3![Frontier logo]()
$97
This Super.com deal was found by Cheapflights users on 8/3. 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 8/266:25 am -
Nonstop2h 38m
Deal found 8/3![Frontier logo]()
$98
This Southwest deal was found by Cheapflights users on 8/3. 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 9/212:25 pm -
1 stop4h 55m
Deal found 8/3![Southwest logo]()
$99
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 August 6, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $128 (Kiwi.com) |
One-way from | $88 (Kiwi.com) |
Popular in | June |
Cheapest in | February |
Average price | $226 |
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 2,558,603 searches. Data last updated August 6, 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
Thu 9/10
10:54 am-6:11 pm
1 stop6h 17m
Denver Intl
Sun 9/20
5:30 am-8:41 am
1 stop4h 11m
$197
San DiegoDenver
SAN San Diego - DEN Denver Intl
SANDEN
San Diego
Wed 9/9
10:54 am-6:11 pm
1 stop6h 17m
Denver Intl
Mon 9/14
7:55 pm-11:47 pm
1 stop4h 52m
$207
San DiegoDenver
SAN San Diego - DEN Denver Intl
SANDEN
San Diego
Thu 9/10
10:54 am-6:11 pm
1 stop6h 17m
Denver Intl
Mon 9/14
7:55 pm-11:47 pm
1 stop4h 52m
$217
San DiegoDenver
SAN San Diego - DEN Denver Intl
SANDEN
San Diego
Sat 8/29
1:55 pm-7:35 pm
1 stop4h 40m
Denver Intl
Sat 9/5
1:35 pm-6:55 pm
2 stops6h 20m
$223
San DiegoDenver
SAN San Diego - DEN Denver Intl
SANDEN
San Diego
Wed 9/23
7:25 am-12:35 pm
1 stop4h 10m
Denver Intl
Sat 9/26
1:35 pm-6:55 pm
2 stops6h 20m
$258
Quickest round-trip
San DiegoDenver
SAN San Diego - DEN Denver Intl
SANDEN
San Diego
Tue 12/22
8:45 am-12:15 pm
Nonstop2h 30m
Denver Intl
Tue 12/29
9:01 pm-10:32 pm
Nonstop2h 31m
$377
San DiegoDenver
SAN San Diego - DEN Denver Intl
SANDEN
San Diego
Thu 8/27
2:24 pm-9:13 pm
1 stop5h 49m
Denver Intl
Sun 8/30
8:00 am-11:35 am
1 stop4h 35m
$397
San DiegoDenver
SAN San Diego - DEN Denver Intl
SANDEN
San Diego
Fri 10/9
2:59 pm-10:37 pm
1 stop6h 38m
Denver Intl
Mon 10/12
7:07 am-1:23 pm
1 stop7h 16m
$637
San DiegoDenver
SAN San Diego - DEN Denver Intl
SANDEN
San Diego
Fri 8/21
3:51 pm-7:26 pm
Nonstop2h 35m
Denver Intl
Sun 8/23
8:06 pm-9:50 pm
Nonstop2h 44m
$667
San DiegoDenver
SAN San Diego - DEN Denver Intl
SANDEN
San Diego
Tue 10/6
1:36 pm-7:34 pm
1 stop4h 58m
Denver Intl
Fri 10/9
10:45 am-7:14 pm
2 stops9h 29m
$715
Showing 1-10 of 24 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 August 6, 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 32% on your trip compared to booking a flight in the afternoon.
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 August 6, 2026.
The most flights from SAN to BD9 are scheduled on a Wednesday (32 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (14 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 $171 and $277 in August.The cheapest round-trip price found within the last 5 days was $128 on Frontier (Aug 27-Sep 1).
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 August 1, 2026.
Travelers seeking maximum savings on their San Diego to Boulder flight should consider departing on Tuesday at noon 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 August 6, 2026.
See what other customers who have flown with Southwest,Alaska Airlines, andHawaiian 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
Food
7.0
Comfort
8.0
Crew
8.6
Entertainment
7.5
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Boarding
8.1
Overall
8.0
Food
7.0
Comfort
8.0
Crew
8.6
Entertainment
7.5
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Boarding
8.1
Overall
8.0
Food
7.0
Comfort
8.0
Crew
8.6
Entertainment
7.5
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Boarding
8.1
Overall
8.0
Food
7.0
Comfort
8.0
Crew
8.6
Entertainment
7.5
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Boarding
8.1
Overall
8.0
Food
7.0
Comfort
8.0
Crew
8.6
Entertainment
7.5
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Boarding
8.1
Overall
8.0
Food
7.0
Comfort
8.0
Crew
8.6
Entertainment
7.5
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Related info for your journey
Find useful and relevant information for your journey from San Diego to Boulder. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.
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San Diego and Boulder flights
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Top 5 airlines flying from San Diego to Boulder
Discover the top 5 airlines that operate flights from San Diego to Boulder. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated August 6, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$47 | Average$142 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$58 | Average$137 | FlexibilityNo cancel fee | On-time85% | |
| Cheapest$116 | Average$208 | FlexibilityNo cancel fee | On-time75% | |
| Cheapest$117 | Average$292 | FlexibilityNo cancel fee | On-time63% | |
| Cheapest$117 | Average$319 | FlexibilityNo cancel fee | On-time69% |