$64+ Cheap flights from San Francisco (SFO) 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 4/20. Fares are subject to change and may not be available on all flights or dates of travel.
SFO — DEN
Apr 15 — Apr 221
Round-trip
1 adult, Economy
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Find cheap flights from San Francisco 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 Francisco to Boulder are usually found in October or April, booked 53 days in advance, depart on a Tuesday or Friday and return on a Friday
Cheap flight deals from San Francisco to Boulder
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Best
Last-minute
One-way
Cheapest flights from San Francisco to BoulderExplore the most affordable flight options available from San Francisco to Boulder. Find the lowest fares from popular airlines and budget airlines, with prices last updated on March 16, 2026.
Explore the most affordable flight options available from San Francisco to Boulder. Find the lowest fares from popular airlines and budget airlines, with prices last updated on March 16, 2026.
This Super.com deal was found by Cheapflights users on 3/12. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/136:00 am
SFO
- DEN
Nonstop2h 47m
Frontier
Fri 4/1710:29 pm
DEN
- SFO
Nonstop2h 58m
Frontier
Deal found 3/12![Frontier logo]()
$118
This Cheapflightsfares deal was found by Cheapflights users on 3/12. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 5/86:00 am
SFO
- DEN
Nonstop2h 42m
Frontier
Sun 5/107:15 am
DEN
- SFO
Nonstop2h 53m
Frontier
Deal found 3/12![Frontier logo]()
$119
This Frontier deal was found by Cheapflights users on 3/11. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 5/116:00 am
SFO
- DEN
Nonstop2h 52m
Frontier
Sat 5/169:47 am
DEN
- SFO
Nonstop2h 55m
Frontier
Deal found 3/11![Frontier logo]()
$120
This Frontier deal was found by Cheapflights users on 3/11. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 4/16:00 am
SFO
- DEN
Nonstop2h 42m
Frontier
Wed 4/110:30 pm
DEN
- SFO
Nonstop2h 53m
Frontier
Deal found 3/11![Frontier logo]()
$124
This WAYA deal was found by Cheapflights users on 3/12. 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 WAYA is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/610:50 pm
SFO
- DEN
1 stop9h 15m
Frontier
Tue 4/76:06 pm
DEN
- SFO
Nonstop2h 59m
Frontier
Deal found 3/12![Frontier logo]()
$125
This Kiwi.com deal was found by Cheapflights users on 3/13. 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.
Thu 4/239:58 am
SFO
- DEN
1 stop29h 01m
Frontier
Mon 4/277:15 am
DEN
- SFO
Nonstop2h 58m
Frontier
Deal found 3/13![Frontier logo]()
$126
This Kiwi.com deal was found by Cheapflights users on 3/14. 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.
Wed 4/156:00 am
SFO
- DEN
Nonstop2h 47m
Frontier
Fri 4/1710:29 pm
DEN
- SFO
Nonstop2h 58m
Frontier
Deal found 3/14![Frontier logo]()
$127
This Kiwi.com deal was found by Cheapflights users on 3/14. 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.
Wed 4/152:47 pm
SFO
- DEN
1 stop8h 32m
Frontier
Wed 4/229:30 pm
DEN
- SFO
1 stop14h 41m
Frontier
Deal found 3/14![Frontier logo]()
$128
This Kiwi.com deal was found by Cheapflights users on 3/11. 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.
Mon 4/133:10 pm
SFO
- DEN
1 stop11h 49m
Frontier
Mon 4/2010:29 pm
DEN
- SFO
Nonstop2h 58m
Frontier
Deal found 3/11![Frontier logo]()
$129
This Super.com deal was found by Cheapflights users on 3/13. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 4/19:00 pm
SFO
- DEN
Nonstop2h 42m
Frontier
Wed 4/810:30 pm
DEN
- SFO
Nonstop2h 58m
Frontier
Deal found 3/13![Frontier logo]()
$130
This Kiwi.com deal was found by Cheapflights users on 3/13. 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.
Tue 4/142:47 pm
SFO
- DEN
1 stop8h 32m
Frontier
Mon 4/2010:29 pm
DEN
- SFO
Nonstop2h 58m
Frontier
Deal found 3/13![Frontier logo]()
$131
This Frontier deal was found by Cheapflights users on 3/12. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/206:00 am
SFO
- DEN
Nonstop2h 47m
Frontier
Wed 4/299:25 pm
DEN
- SFO
Nonstop3h 00m
Frontier
Deal found 3/12![Frontier logo]()
$132
Best flights from San Francisco to BoulderDiscover carefully curated flight deals from San Francisco to Boulder that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated March 16, 2026.
Discover carefully curated flight deals from San Francisco to Boulder that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated March 16, 2026.
This Delta deal was found by Cheapflights users on 3/11. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 5/124:53 pm
SFO
- DEN
1 stop4h 48m
Delta
Fri 5/153:49 pm
DEN
- SFO
1 stop6h 41m
Delta
Deal found 3/11![Delta logo]()
$237
This Southwest deal was found by Cheapflights users on 3/12. 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.
Wed 4/158:20 am
SFO
- DEN
2 stops7h 45m
Southwest
Wed 4/2210:10 am
DEN
- SFO
2 stops6h 10m
Southwest
Deal found 3/12![Southwest logo]()
$303
This Alaska Airlines deal was found by Cheapflights users on 3/14. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 4/106:35 am
SFO
- DEN
1 stop9h 49m
Alaska Airlines
Mon 4/136:20 pm
DEN
- SFO
1 stop16h 13m
Alaska Airlines
Deal found 3/14![Alaska Airlines logo]()
$359
This United Airlines deal was found by Cheapflights users on 3/15. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/65:00 am
SFO
- DEN
Nonstop2h 40m
United Airlines
Fri 4/105:15 am
DEN
- SFO
Nonstop2h 50m
United Airlines
Deal found 3/15![United Airlines logo]()
$407
This Delta deal was found by Cheapflights users on 3/11. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 5/139:30 am
SFO
- DEN
1 stop7h 05m
Delta
Thu 5/216:19 pm
DEN
- SFO
1 stop6h 38m
Delta
Deal found 3/11![Delta logo]()
$277
This Southwest deal was found by Cheapflights users on 3/16. 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.
Thu 4/307:25 am
SFO
- DEN
2 stops6h 30m
Southwest
Thu 5/78:40 am
DEN
- SFO
2 stops6h 05m
Southwest
Deal found 3/16![Southwest logo]()
$337
This Southwest deal was found by Cheapflights users on 3/11. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/133:40 pm
SFO
- DEN
2 stops7h 05m
Southwest
Mon 4/205:10 pm
DEN
- SFO
2 stops6h 15m
Southwest
Deal found 3/11![Southwest logo]()
$377
This Delta deal was found by Cheapflights users on 3/16. 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 5/234:55 pm
SFO
- DEN
1 stop5h 49m
Delta
Mon 5/255:30 am
DEN
- SFO
1 stop4h 23m
Delta
Deal found 3/16![Delta logo]()
$378
This Alaska Airlines deal was found by Cheapflights users on 3/14. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/67:20 am
SFO
- DEN
2 stops9h 04m
Alaska Airlines
Fri 4/106:03 pm
DEN
- SFO
1 stop6h 26m
Alaska Airlines
Deal found 3/14![Alaska Airlines logo]()
$433
This Southwest deal was found by Cheapflights users on 3/11. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 4/227:40 am
SFO
- DEN
2 stops8h 30m
Southwest
Sat 4/2510:10 am
DEN
- SFO
2 stops8h 15m
Southwest
Deal found 3/11![Southwest logo]()
$388
This Southwest deal was found by Cheapflights users on 3/11. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 5/36:00 am
SFO
- DEN
2 stops9h 00m
Southwest
Wed 5/610:10 am
DEN
- SFO
2 stops6h 10m
Southwest
Deal found 3/11![Southwest logo]()
$389
This Southwest deal was found by Cheapflights users on 3/14. 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.
Tue 6/27:40 am
SFO
- DEN
2 stops8h 30m
Southwest
Sun 6/78:00 am
DEN
- SFO
2 stops6h 35m
Southwest
Deal found 3/14![Southwest logo]()
$407
Last-minute flights from San Francisco to BoulderDiscover last-minute flight deals from San Francisco to Boulder. Data last updated March 16, 2026 and is based on user searches.
Discover last-minute flight deals from San Francisco to Boulder. Data last updated March 16, 2026 and is based on user searches.
This Frontier deal was found by Cheapflights users on 3/11. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 4/16:00 am
SFO
- DEN
Nonstop2h 42m
Frontier
Wed 4/110:30 pm
DEN
- SFO
Nonstop2h 53m
Frontier
Deal found 3/11![Frontier logo]()
$124
This Super.com deal was found by Cheapflights users on 3/13. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 4/19:00 pm
SFO
- DEN
Nonstop2h 42m
Frontier
Wed 4/810:30 pm
DEN
- SFO
Nonstop2h 58m
Frontier
Deal found 3/13![Frontier logo]()
$130
This WAYA deal was found by Cheapflights users on 3/12. 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 WAYA is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/610:50 pm
SFO
- DEN
1 stop9h 15m
Frontier
Tue 4/76:06 pm
DEN
- SFO
Nonstop2h 59m
Frontier
Deal found 3/12![Frontier logo]()
$125
This Super.com deal was found by Cheapflights users on 3/12. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/136:00 am
SFO
- DEN
Nonstop2h 47m
Frontier
Fri 4/1710:29 pm
DEN
- SFO
Nonstop2h 58m
Frontier
Deal found 3/12![Frontier logo]()
$118
This Kiwi.com deal was found by Cheapflights users on 3/11. 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.
Mon 4/133:10 pm
SFO
- DEN
1 stop11h 49m
Frontier
Mon 4/2010:29 pm
DEN
- SFO
Nonstop2h 58m
Frontier
Deal found 3/11![Frontier logo]()
$129
This Kiwi.com deal was found by Cheapflights users on 3/13. 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.
Tue 4/142:47 pm
SFO
- DEN
1 stop8h 32m
Frontier
Mon 4/2010:29 pm
DEN
- SFO
Nonstop2h 58m
Frontier
Deal found 3/13![Frontier logo]()
$131
This Kiwi.com deal was found by Cheapflights users on 3/14. 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.
Wed 4/156:00 am
SFO
- DEN
Nonstop2h 47m
Frontier
Fri 4/1710:29 pm
DEN
- SFO
Nonstop2h 58m
Frontier
Deal found 3/14![Frontier logo]()
$127
This Kiwi.com deal was found by Cheapflights users on 3/14. 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.
Wed 4/152:47 pm
SFO
- DEN
1 stop8h 32m
Frontier
Wed 4/229:30 pm
DEN
- SFO
1 stop14h 41m
Frontier
Deal found 3/14![Frontier logo]()
$128
This Cheapflightsfares deal was found by Cheapflights users on 3/13. 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 4/1711:16 pm
SFO
- DEN
1 stop13h 24m
Frontier
Tue 4/289:25 pm
DEN
- SFO
Nonstop3h 00m
Frontier
Deal found 3/13![Frontier logo]()
$133
This Kiwi.com deal was found by Cheapflights users on 3/13. 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.
Sat 4/182:47 pm
SFO
- DEN
1 stop8h 32m
Frontier
Mon 4/2010:29 pm
DEN
- SFO
Nonstop2h 58m
Frontier
Deal found 3/13![Frontier logo]()
$134
This Frontier deal was found by Cheapflights users on 3/12. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/206:00 am
SFO
- DEN
Nonstop2h 47m
Frontier
Wed 4/299:25 pm
DEN
- SFO
Nonstop3h 00m
Frontier
Deal found 3/12![Frontier logo]()
$132
This Kiwi.com deal was found by Cheapflights users on 3/13. 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.
Thu 4/239:58 am
SFO
- DEN
1 stop29h 01m
Frontier
Mon 4/277:15 am
DEN
- SFO
Nonstop2h 58m
Frontier
Deal found 3/13![Frontier logo]()
$126
One-way flights from San Francisco to BoulderSearch for one-way flight options from San Francisco to Boulder. Find affordable one-way fares based on user searches. Data last updated March 16, 2026.
Search for one-way flight options from San Francisco to Boulder. Find affordable one-way fares based on user searches. Data last updated March 16, 2026.
This Kiwi.com deal was found by Cheapflights users on 3/15. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/209:58 am
SFO
- DEN
1 stop23h 52m
Frontier
Deal found 3/15![Frontier logo]()
$64
This Trip.com deal was found by Cheapflights users on 3/12. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 4/217:40 pm
SFO
- DEN
1 stop7h 19m
Frontier
Deal found 3/12![Frontier logo]()
$65
This Kiwi.com deal was found by Cheapflights users on 3/13. 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.
Mon 4/133:10 pm
SFO
- DEN
1 stop11h 49m
Frontier
Deal found 3/13![Frontier logo]()
$67
This WAYA deal was found by Cheapflights users on 3/14. 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 WAYA is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 4/142:47 pm
SFO
- DEN
1 stop8h 32m
Frontier
Deal found 3/14![Frontier logo]()
$68
This Frontier deal was found by Cheapflights users on 3/12. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 3/319:04 pm
SFO
- DEN
Nonstop2h 33m
Frontier
Deal found 3/12![Frontier logo]()
$69
This Kiwi.com deal was found by Cheapflights users on 3/13. 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.
Tue 5/195:36 pm
SFO
- DEN
1 stop8h 49m
Frontier
Deal found 3/13![Frontier logo]()
$70
This Kiwi.com deal was found by Cheapflights users on 3/11. 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.
Mon 5/1110:40 pm
SFO
- DEN
1 stop9h 58m
Frontier
Deal found 3/11![Frontier logo]()
$71
This WAYA deal was found by Cheapflights users on 3/12. 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 WAYA is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 4/76:34 pm
SFO
- DEN
1 stop8h 25m
Frontier
Deal found 3/12![Frontier logo]()
$77
This Kiwi.com deal was found by Cheapflights users on 3/12. 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.
Tue 6/92:16 pm
SFO
- DEN
1 stop6h 13m
Frontier
Deal found 3/12![Frontier logo]()
$78
This Super.com deal was found by Cheapflights users on 3/15. 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.
Thu 4/2311:56 am
SFO
- DEN
Nonstop2h 51m
Frontier
Deal found 3/15![Frontier logo]()
$79
This Frontier deal was found by Cheapflights users on 3/16. 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.
Fri 4/176:00 am
SFO
- DEN
Nonstop2h 47m
Frontier
Deal found 3/16![Frontier logo]()
$80
Find flight deals from San Francisco to Boulder
Keep the following information in mind while searching for San Francisco to Boulder flight deals. Data was last updated March 16, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $118 (Super.com) |
One-way from | $64 (Kiwi.com) |
Popular in | December |
Cheapest in | October |
Average price | $263 |
Cheapflights Fare Finder
Customize your flight search to find flights from San Francisco 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 March 16, 2026.
Use the filters below to find and compare flights from San Francisco to Boulder that are best for you.
Fly from
Fly to
Route
Depart
Return
Cheapest round-trip
San FranciscoDenver
SFO - DEN
SFODEN
San Francisco
Tue 5/12
4:53 pm-10:41 pm
1 stop4h 48m
Denver Intl
Fri 5/15
3:49 pm-9:30 pm
1 stop6h 41m
$237
San FranciscoDenver
SFO - DEN
SFODEN
San Francisco
Wed 5/13
9:30 am-5:35 pm
1 stop7h 05m
Denver Intl
Thu 5/21
6:19 pm-11:57 pm
1 stop6h 38m
$277
San FranciscoDenver
SFO - DEN
SFODEN
San Francisco
Wed 4/15
8:20 am-5:05 pm
2 stops7h 45m
Denver Intl
Wed 4/22
10:10 am-3:20 pm
2 stops6h 10m
$303
San FranciscoDenver
SFO - DEN
SFODEN
San Francisco
Thu 4/30
7:25 am-2:55 pm
2 stops6h 30m
Denver Intl
Thu 5/7
8:40 am-1:45 pm
2 stops6h 05m
$337
San FranciscoDenver
SFO - DEN
SFODEN
San Francisco
Fri 4/10
6:35 am-5:24 pm
1 stop9h 49m
Denver Intl
Mon 4/13
6:20 pm-9:33 am
1 stop16h 13m
$359
San FranciscoDenver
SFO - DEN
SFODEN
San Francisco
Mon 4/13
3:40 pm-11:45 pm
2 stops7h 05m
Denver Intl
Mon 4/20
5:10 pm-10:25 pm
2 stops6h 15m
$377
San FranciscoDenver
SFO - DEN
SFODEN
San Francisco
Sat 5/23
4:55 pm-11:44 pm
1 stop5h 49m
Denver Intl
Mon 5/25
5:30 am-8:53 am
1 stop4h 23m
$378
San FranciscoDenver
SFO - DEN
SFODEN
San Francisco
Wed 4/22
7:40 am-5:10 pm
2 stops8h 30m
Denver Intl
Sat 4/25
10:10 am-5:25 pm
2 stops8h 15m
$388
San FranciscoDenver
SFO - DEN
SFODEN
San Francisco
Sun 5/3
6:00 am-4:00 pm
2 stops9h 00m
Denver Intl
Wed 5/6
10:10 am-3:20 pm
2 stops6h 10m
$389
Quickest round-trip
San FranciscoDenver
SFO - DEN
SFODEN
San Francisco
Mon 4/6
5:00 am-8:40 am
Nonstop2h 40m
Denver Intl
Fri 4/10
5:15 am-7:05 am
Nonstop2h 50m
$407
Showing 1-10 of 23 resultsSorted by cheapest first
Best time to book a flight from San Francisco to Boulder
Have a flexible travel schedule? Discover the best time to fly to Boulder from San Francisco with our price prediction graph.
SFO-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 Francisco to Boulder
SFO-BD9
SFO-DEN
How far ahead should I book a flight from San Francisco to Boulder?
Use this chart to determine the optimal time to book a round-trip flight from San Francisco to Boulder. Price data was last updated on March 13, 2026.
Booking 53 days in advance of your planned departure date is, on average, the best time to get cheap flights from San Francisco to Boulder. The general trend is that the closer you book to the departure date, the more expensive your flight will be.
What is the cheapest month to book a flight from San Francisco to Boulder?
Currently, January is the cheapest month in which you can book a flight from San Francisco to Boulder (average of $58). Flying from San Francisco to Boulder in July is currently the most expensive (average of $107). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.
What is the cheapest time of day to fly from SFO to BD9?
Find hourly flight availability from San Francisco 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 March 16, 2026.
It’s typically best to fly out from San Francisco to Boulder in the evening. Doing so could potentially save you 32% on the flight price compared to flying at noon, which is usually more expensive.
What is the cheapest day to fly from San Francisco to Boulder?
Use this chart to determine the cheapest time to fly round-trip from San Francisco to Boulder. Price data was last updated on March 14, 2026.
Travelers seeking maximum savings on their San Francisco to Boulder flight should consider departing on Friday evenings when fares are most often at their lowest. Sunday at noon flights should be avoided if possible as fares are typically the most expensive at this time.
Weekly flight availability from San Francisco to Boulder
Explore weekly flight availability from San Francisco 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 March 16, 2026.
The most flights from SFO to BD9 are scheduled on a Friday (61 on average). You will have fewer flight options on Tuesday, which is when the least amount of flights are scheduled (39 on average).
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 March 16, 2026.
Peruse reviews from past customers who have flown with Southwest,Delta, andUnited Airlines from San Francisco to Boulder to help guide your decision. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
Boarding
8.1
Crew
8.6
Entertainment
7.5
Food
7.0
Overall
8.0
Comfort
8.0
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Boarding
8.1
Crew
8.6
Entertainment
7.5
Food
7.0
Overall
8.0
Comfort
8.0
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Boarding
8.1
Crew
8.6
Entertainment
7.5
Food
7.0
Overall
8.0
Comfort
8.0
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Boarding
8.1
Crew
8.6
Entertainment
7.5
Food
7.0
Overall
8.0
Comfort
8.0
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Boarding
8.1
Crew
8.6
Entertainment
7.5
Food
7.0
Overall
8.0
Comfort
8.0
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Boarding
8.1
Crew
8.6
Entertainment
7.5
Food
7.0
Overall
8.0
Comfort
8.0
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 Francisco to Boulder. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.
Browse thousands of different options on Cheapflights for your next trip
Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.
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Alternative routes for San Francisco to Boulder
See prices for flight routes from nearby airports that may be better suited for you.
Complete your trip
Complete your trip to Boulder by adding a car rental and/or hotel reservation to your travel itinerary.
Search flights from San Francisco to Boulder by cabin class
Find flights from San Francisco to Boulder, based on your preferred cabin class, be it economy, premium economy, business, or first class.
San Francisco and Boulder flights
Browse other San Francisco and Boulder flight options. Last updated on March 16, 2026.
Other flights from San Francisco
Browse through other flights departing from San Francisco. Flights are based on user searches made on Cheapflights and were last updated on March 16, 2026.
Popular flight searches
Check out other popular destinations found by fellow travelers in 2026
San Francisco to Boulder flights
Consider these flights traveling from San Francisco to Boulder.
Top 7 airlines flying from San Francisco to Boulder
Discover the top 7 airlines that operate flights from San Francisco 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 March 16, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$76 | Average$200 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$87 | Average$96 | FlexibilityNo cancel fee | On-time88% | |
| Cheapest$128 | Average$290 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$157 | Average$357 | FlexibilityNo cancel fee | On-time63% | |
| Cheapest$163 | Average$383 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$176 | Average$478 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$226 | Average$337 | FlexibilityNo cancel fee | On-time62% |