How popular is this San Francisco to Boulder flight route?

This flight path from San Francisco to Boulder was viewed by 280 users in the past month. Keep an eye out for changes in search interest prior to high and low season.

What are the cheapest airlines to fly from San Francisco to Boulder one-way?

For one-way options, check prices for Frontier. According to our data, you can fly for as low as $46. Users have also found prices from $77 and $107 on JetBlue and United Airlines, respectively.

Weekly flight availability from San Francisco to Boulder

The most flights from SFO to BD9 are scheduled on a Tuesday (54 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (30 on average).

In terms of precipitation, rainfall in Boulder ranges from 0.5 - 2.3 inches per month. May is typically the wettest month, when rainfall can reach 2.3 in. January is typically the driest time to visit Boulder when rainfall is around 0.5 in.

If weather is an important factor for your trip to Boulder, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 73.4 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 30.2 F).

What are the cheapest flights from San Francisco to Boulder?

The cheapest flight price from San Francisco to Boulder is $117. On average you can expect to pay $841. The most popular route, (San Francisco - Denver Intl), can usually be booked for $107.

What are the most reliable airlines from San Francisco to Boulder?

Consider Asiana Airlines (83%), United Airlines (82%) or Virgin Australia (79%) when booking your flight. These represent the most reliable airlines when flying from San Francisco to Boulder.

What are the most popular airlines that fly from San Francisco to Boulder?

Consider Frontier, United Airlines or Southwest when booking your flight. These represent the most popular airlines when flying from San Francisco to Boulder.

What airport do you fly from for flights from San Francisco to Boulder?

Located just 11.0 mi from the city center, San Francisco is the airport most travelers will use when flying to Boulder from San Francisco. Booking flights from San Francisco (SFO) to Boulder should be relatively easy as there are 44 daily outbound flights to Boulder from 5 different airlines.

Can I find deals for flights from San Francisco to Boulder that include hotel bookings?

Yes. In addition to deals on San Francisco to Boulder flights, Cheapflights offers vacation packages that include both flights and hotel.

How can I find direct flights from San Francisco to Boulder?

After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from San Francisco to Boulder.

Can I find deals for business class flights from San Francisco to Boulder?

Yes. Cheapflights offers flight deals from San Francisco to Boulder by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

Find Cheap Flights from San Francisco to Boulder

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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

Find flight deals from San Francisco to Boulder

Most accurate provider	FlightHub 3 stars
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Popular in	June
Cheapest in	February
Average price	$307

Provider with most accurate pricing for San Francisco-Denver Intl flight deals.

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Highest demand for flights based on searches. 12% potential increase in price ($44 potential increase over avg. RT price).

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Cheapest flight prices on average. 1% potential price decrease ($7 potential savings vs. average RT price).

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Average for round-trip flights in November 2026

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Everything you need to know about your flight from San Francisco to Boulder

Prices

Airlines

What is the cheapest time of day to fly from SFO to BD9?

It’s typically best to fly out from San Francisco to Boulder in the evening. Doing so could potentially save you 26% 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?

Travelers seeking maximum savings on their San Francisco to Boulder flight should consider departing on Wednesday 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

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.

Southwest

8.0

Very good

4,211 reviews

Reviews

1 / 20

2.0

Mediocre

Thomas,Dec 2025

SEA - DEN

Plane two hours late in leaving 1:00 pm west coat time got home next day at 2:45am most car rental places are closed and don’t open till 5am

Southwest

8.0

Very good

4,211 reviews

Southwest

8.0

Very good

4,211 reviews

Reviews

1 / 20

2.0

Mediocre

Thomas,Dec 2025

SEA - DEN

Plane two hours late in leaving 1:00 pm west coat time got home next day at 2:45am most car rental places are closed and don’t open till 5am

Delta

7.8

Good

8,698 reviews

Southwest

8.0

Very good

4,211 reviews

Reviews

1 / 20

2.0

Mediocre

Thomas,Dec 2025

SEA - DEN

Plane two hours late in leaving 1:00 pm west coat time got home next day at 2:45am most car rental places are closed and don’t open till 5am

United Airlines

7.3

Good

10,458 reviews

Southwest

8.0

Very good

4,211 reviews

Reviews

1 / 20

2.0

Mediocre

Thomas,Dec 2025

SEA - DEN

Plane two hours late in leaving 1:00 pm west coat time got home next day at 2:45am most car rental places are closed and don’t open till 5am

JetBlue

7.1

Good

3,063 reviews

Southwest

8.0

Very good

4,211 reviews

Reviews

1 / 20

2.0

Mediocre

Thomas,Dec 2025

SEA - DEN

Plane two hours late in leaving 1:00 pm west coat time got home next day at 2:45am most car rental places are closed and don’t open till 5am

Frontier

5.5

Fair

2,512 reviews

Southwest

8.0

Very good

4,211 reviews

Reviews

1 / 20

2.0

Mediocre

Thomas,Dec 2025

SEA - DEN

Plane two hours late in leaving 1:00 pm west coat time got home next day at 2:45am most car rental places are closed and don’t open till 5am

Related info for your journey

What airport do you fly from for flights from San Francisco to Boulder?
Located just 11.0 mi from the city center, San Francisco is the airport most travelers will use when flying to Boulder from San Francisco. Booking flights from San Francisco (SFO) to Boulder should be relatively easy as there are 44 daily outbound flights to Boulder from 5 different airlines.
How popular is this San Francisco to Boulder flight route?
This flight path from San Francisco to Boulder was viewed by 280 users in the past month. Keep an eye out for changes in search interest prior to high and low season.
What are the cheapest airlines to fly from San Francisco to Boulder one-way?
For one-way options, check prices for Frontier. According to our data, you can fly for as low as $46. Users have also found prices from $77 and $107 on JetBlue and United Airlines, respectively.
What are the most reliable airlines from San Francisco to Boulder?
Consider Asiana Airlines (83%), United Airlines (82%) or Virgin Australia (79%) when booking your flight. These represent the most reliable airlines when flying from San Francisco to Boulder.
What are the cheapest flights from San Francisco to Boulder?
The cheapest flight price from San Francisco to Boulder is $117. On average you can expect to pay $841. The most popular route, (San Francisco - Denver Intl), can usually be booked for $107.
Can I find deals for flights from San Francisco to Boulder that include hotel bookings?
Yes. In addition to deals on San Francisco to Boulder flights, Cheapflights offers vacation packages that include both flights and hotel.
How can I find direct flights from San Francisco to Boulder?
After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from San Francisco to Boulder.
Can I find deals for business class flights from San Francisco to Boulder?
Yes. Cheapflights offers flight deals from San Francisco to Boulder by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

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Top 5 airlines flying from San Francisco to Boulder

Airline	Cheapest	Average	Flexibility	On-time
Frontier	Cheapest$91	Average$267	FlexibilityNo cancel fee	On-time62%
Delta	Cheapest$121	Average$423	FlexibilityNo cancel fee	On-timeN/A
United Airlines	Cheapest$204	Average$425	FlexibilityNo cancel fee	On-time69%
Southwest	Cheapest$213	Average$405	FlexibilityNo cancel fee	On-time63%
JetBlue	Cheapest$221	Average$392	FlexibilityNo cancel fee	On-time62%

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Cheap flights from San Francisco (SFO) to Boulder, CO

Find cheap flights from San Francisco to Boulder with Cheapflights

1. Tell us where you want to go

2. Select your favorite providers

3. Compare prices and book

Find flight deals from San Francisco to Boulder

Most accurate provider

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Popular in

Cheapest in

Average price

Cheapflights Insights

What is the cheapest time of day to fly from SFO to BD9?

It’s typically best to fly out from San Francisco to Boulder in the evening. Doing so could potentially save you 26% 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?

Travelers seeking maximum savings on their San Francisco to Boulder flight should consider departing on Wednesday 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

The most flights from SFO to BD9 are scheduled on a Tuesday (54 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (30 on average).

Reviews of airlines servicing Boulder

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.

Related info for your journey

What airport do you fly from for flights from San Francisco to Boulder?

How popular is this San Francisco to Boulder flight route?

What are the cheapest airlines to fly from San Francisco to Boulder one-way?

What are the most reliable airlines from San Francisco to Boulder?

What are the cheapest flights from San Francisco to Boulder?

Can I find deals for flights from San Francisco to Boulder that include hotel bookings?

How can I find direct flights from San Francisco to Boulder?

Can I find deals for business class flights from San Francisco to Boulder?

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.

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 November 5, 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 November 5, 2026.

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