$97+ Cheap flights from San Francisco (SFO) 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 11/8. Fares are subject to change and may not be available on all flights or dates of travel.
SFO — DEN
Oct 17 — Oct 241
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 February or January, booked 71 days in advance, depart on a Wednesday or Saturday and return on a Friday
Cheap flight deals from San Francisco to Boulder
Cheapest
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 September 17, 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 September 17, 2026.
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 11/239:23 pm -
Nonstop2h 40m
Thu 11/264:00 pm -
Nonstop2h 54m
Deal found 9/14![Frontier logo]()
$172
This CheapOair deal was found by Cheapflights users on 9/16. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/1210:19 pm -
1 stop10h 30m
Sun 10/2510:29 pm -
Nonstop2h 46m
Deal found 9/16![Frontier logo]()
$173
This Kiwi.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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/106:00 am -
Nonstop2h 46m
Thu 10/159:16 am -
Nonstop2h 49m
Deal found 9/15![Frontier logo]()
$174
This Cheapflightsfares deal was found by Cheapflights users on 9/16. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/228:58 am -
1 stop5h 16m
Mon 10/262:39 pm -
1 stop23h 12m
Deal found 9/16![Frontier logo]()
$175
This Kiwi.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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/2812:20 pm -
Nonstop2h 39m
Thu 11/510:29 pm -
Nonstop2h 51m
Deal found 9/15![Frontier logo]()
$176
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.
Thu 10/296:02 am -
Nonstop2h 38m
Mon 11/210:41 am -
1 stop10h 59m
Deal found 9/14![Frontier logo]()
$177
This Cheapflightsfares deal was found by Cheapflights users on 9/16. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/256:04 am -
Nonstop2h 42m
Fri 10/210:29 pm -
Nonstop2h 45m
Deal found 9/16![Frontier logo]()
$178
This CheapOair deal was found by Cheapflights users on 9/16. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 10/116:00 am -
Nonstop2h 46m
Thu 10/1510:29 pm -
Nonstop2h 46m
Deal found 9/16![Frontier logo]()
$179
This Frontier deal was found by Cheapflights users on 9/16. 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.
Mon 9/286:04 am -
Nonstop2h 42m
Fri 10/210:29 pm -
Nonstop2h 45m
Deal found 9/16![Frontier logo]()
$180
This CheapOair deal was found by Cheapflights users on 9/16. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/16:04 am -
Nonstop2h 42m
Wed 10/71:05 pm -
1 stop20h 08m
Deal found 9/16![Frontier logo]()
$181
This iWofly 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 iWofly is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/226:04 am -
Nonstop2h 42m
Wed 9/2310:29 pm -
Nonstop2h 45m
Deal found 9/15![Frontier logo]()
$182
This Cheapflightsfares deal was found by Cheapflights users on 9/17. 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 10/175:48 pm -
1 stop4h 55m
Mon 10/1910:29 pm -
Nonstop2h 46m
Deal found 9/17![Frontier logo]()
$183
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 September 17, 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 September 17, 2026.
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.
Sat 10/245:00 am -
1 stop7h 30m
Tue 10/274:00 pm -
2 stops6h 05m
Deal found 9/14![Southwest logo]()
$253
This Delta deal was found by Cheapflights users on 9/16. 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.
Mon 11/25:18 pm -
1 stop5h 35m
Tue 11/1710:45 am -
2 stops10h 32m
Deal found 9/16![Delta logo]()
$338
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.
Thu 12/108:00 am -
1 stop5h 24m
Tue 12/151:54 pm -
1 stop5h 12m
Deal found 9/13![Alaska Airlines logo]()
$345
This Southwest 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/2912:05 pm -
1 stop5h 40m
Mon 11/27:15 pm -
2 stops5h 50m
Deal found 9/15![Southwest logo]()
$286
This Southwest 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 12/225:55 pm -
1 stop5h 45m
Fri 12/253:45 pm -
2 stops6h 45m
Deal found 9/15![Southwest logo]()
$307
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.
Wed 2/106:45 am -
1 stop4h 45m
Fri 2/196:30 pm -
2 stops6h 20m
Deal found 9/14![Southwest logo]()
$308
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.
Sat 12/122:55 pm -
1 stop6h 05m
Tue 12/1512:49 pm -
1 stop4h 36m
Deal found 9/13![Delta logo]()
$387
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.
Tue 9/293:25 pm -
1 stop4h 48m
Sat 10/312:31 pm -
1 stop4h 45m
Deal found 9/13![Alaska Airlines logo]()
$393
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.
Thu 12/104:35 pm -
1 stop6h 28m
Wed 12/165:35 am -
1 stop4h 34m
Deal found 9/13![Delta logo]()
$387
This Delta 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/301:20 pm -
1 stop5h 20m
Thu 10/85:25 am -
1 stop4h 26m
Deal found 9/12![Delta logo]()
$417
This Southwest 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/315:10 am -
2 stops7h 55m
Sun 11/810:25 am -
2 stops6h 15m
Deal found 9/15![Southwest logo]()
$401
Last-minute flights from San Francisco to BoulderDiscover last-minute flight deals from San Francisco to Boulder. Data last updated September 17, 2026 and is based on user searches.
Discover last-minute flight deals from San Francisco to Boulder. Data last updated September 17, 2026 and is based on user searches.
This iWofly 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 iWofly is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/226:04 am -
Nonstop2h 42m
Wed 9/2310:29 pm -
Nonstop2h 45m
Deal found 9/15![Frontier logo]()
$182
This Cheapflightsfares 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/256:04 am -
Nonstop2h 42m
Sun 9/276:55 am -
Nonstop2h 49m
Deal found 9/15![Frontier logo]()
$178
This Frontier deal was found by Cheapflights users on 9/16. 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.
Mon 9/286:04 am -
Nonstop2h 42m
Fri 10/210:29 pm -
Nonstop2h 45m
Deal found 9/16![Frontier logo]()
$180
This CheapOair deal was found by Cheapflights users on 9/16. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/16:04 am -
Nonstop2h 42m
Wed 10/71:05 pm -
1 stop20h 08m
Deal found 9/16![Frontier logo]()
$181
This Kiwi.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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/106:00 am -
Nonstop2h 46m
Mon 10/194:33 pm -
Nonstop2h 45m
Deal found 9/15![Frontier logo]()
$174
This CheapOair deal was found by Cheapflights users on 9/16. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 10/116:00 am -
Nonstop2h 46m
Thu 10/1510:29 pm -
Nonstop2h 46m
Deal found 9/16![Frontier logo]()
$179
This CheapOair deal was found by Cheapflights users on 9/16. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/1210:19 pm -
1 stop10h 30m
Sun 10/2510:29 pm -
Nonstop2h 46m
Deal found 9/16![Frontier logo]()
$173
This Super.com deal was found by Cheapflights users on 9/16. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/156:00 am -
Nonstop2h 46m
Wed 10/2110:29 pm -
Nonstop2h 46m
Deal found 9/16![Frontier logo]()
$172
This Cheapflightsfares deal was found by Cheapflights users on 9/17. 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 10/175:48 pm -
1 stop4h 55m
Mon 10/1910:29 pm -
Nonstop2h 46m
Deal found 9/17![Frontier logo]()
$183
This Cheapflightsfares deal was found by Cheapflights users on 9/16. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/228:58 am -
1 stop5h 16m
Mon 10/262:39 pm -
1 stop23h 12m
Deal found 9/16![Frontier logo]()
$175
This Kiwi.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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/2812:20 pm -
Nonstop2h 39m
Thu 11/510:29 pm -
Nonstop2h 51m
Deal found 9/15![Frontier logo]()
$176
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.
Thu 10/296:02 am -
Nonstop2h 38m
Mon 11/210:41 am -
1 stop10h 59m
Deal found 9/14![Frontier logo]()
$177
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 September 17, 2026.
Search for one-way flight options from San Francisco to Boulder. Find affordable one-way fares based on user searches. Data last updated September 17, 2026.
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.
Sun 11/84:57 pm -
1 stop16h 02m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/14![Frontier logo]()
$97
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.
Thu 10/1511:22 am -
1 stop8h 02m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/13![Frontier logo]()
$100
This CheapOair 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/512:07 pm -
1 stop20h 25m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/14![Frontier logo]()
$101
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.
Thu 10/88:58 am -
1 stop5h 16m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/14![Frontier logo]()
$103
This Frontier deal was found by Cheapflights users on 9/17. 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 2/312:54 pm -
1 stop6h 25m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/17![Frontier logo]()
$104
This Kiwi.com deal was found by Cheapflights users on 9/17. 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 9/236:04 am -
Nonstop2h 42m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/17![Frontier logo]()
$108
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 September 17, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $172 (Frontier) |
One-way from | $97 (Super.com) |
Popular in | June |
Cheapest in | February |
Average price | $298 |
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 7,457,451 searches. Data last updated September 17, 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 San Francisco - DEN Denver Intl
SFODEN
San Francisco
Wed 2/3
7:00 am-1:57 pm
1 stop5h 57m
Denver Intl
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$116
San FranciscoDenver
SFO San Francisco - DEN Denver Intl
SFODEN
San Francisco
Tue 12/15
5:05 am-12:45 pm
1 stop6h 40m
Denver Intl
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$126
San FranciscoDenver
SFO San Francisco - DEN Denver Intl
SFODEN
San Francisco
Tue 10/13
5:13 pm-10:40 pm
1 stop4h 27m
Denver Intl
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$126
San FranciscoDenver
SFO San Francisco - DEN Denver Intl
SFODEN
San Francisco
Mon 11/30
6:16 am-9:55 am
Nonstop2h 39m
Denver Intl
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$184
Quickest round-trip
San FranciscoDenver
SFO San Francisco - DEN Denver Intl
SFODEN
San Francisco
Thu 10/8
6:00 am-9:30 am
Nonstop2h 30m
Denver Intl
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$184
San FranciscoDenver
SFO San Francisco - DEN Denver Intl
SFODEN
San Francisco
Mon 1/4
5:05 am-12:50 pm
2 stops6h 45m
Denver Intl
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$199
San FranciscoDenver
SFO San Francisco - DEN Denver Intl
SFODEN
San Francisco
Fri 3/12
8:52 pm-12:43 am
Nonstop2h 51m
Denver Intl
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$205
San FranciscoDenver
SFO San Francisco - DEN Denver Intl
SFODEN
San Francisco
Thu 12/17
10:15 am-11:59 pm
2 stops12h 44m
Denver Intl
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$207
San FranciscoDenver
SFO San Francisco - DEN Denver Intl
SFODEN
San Francisco
Mon 10/5
5:00 am-8:40 am
Nonstop2h 40m
Denver Intl
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$207
San FranciscoDenver
SFO San Francisco - DEN Denver Intl
SFODEN
San Francisco
Wed 3/10
8:00 am-6:33 pm
2 stops9h 33m
Denver Intl
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$207
Showing 1-10 of 21 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
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 September 17, 2026.
It’s typically best to fly out from San Francisco to Boulder in the evening. Doing so could potentially save you 27% on the flight price compared to flying at noon, which is usually more expensive.
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 September 17, 2026.
The most flights from SFO to BD9 are scheduled on a Wednesday (55 on average). You will have fewer flight options on Tuesday, which is when the least amount of flights are scheduled (21 on average).
How much does it cost to fly round-trip from San Francisco to Boulder?
Airfare is below average for this route at the moment.
San Francisco to Boulder flights typically cost between $229 and $401 in November.The cheapest round-trip price found within the last 5 days was $172 on Frontier (Nov 23-Nov 26).
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 September 12, 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.
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 17, 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.
Overall
8.0
Food
7.0
Crew
8.6
Entertainment
7.5
Boarding
8.1
Comfort
8.0
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Overall
8.0
Food
7.0
Crew
8.6
Entertainment
7.5
Boarding
8.1
Comfort
8.0
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Overall
8.0
Food
7.0
Crew
8.6
Entertainment
7.5
Boarding
8.1
Comfort
8.0
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Overall
8.0
Food
7.0
Crew
8.6
Entertainment
7.5
Boarding
8.1
Comfort
8.0
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Overall
8.0
Food
7.0
Crew
8.6
Entertainment
7.5
Boarding
8.1
Comfort
8.0
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Overall
8.0
Food
7.0
Crew
8.6
Entertainment
7.5
Boarding
8.1
Comfort
8.0
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
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| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$86 | Average$252 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$178 | Average$403 | FlexibilityNo cancel fee | On-time63% | |
| Cheapest$193 | Average$400 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$196 | Average$415 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$226 | Average$362 | FlexibilityNo cancel fee | On-time62% |