Cheap flights from San Diego (SAN) to Boulder, CO
SAN — DEN
Dec 4 — Dec 111
Round-trip
1 adult, Economy
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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 57 days in advance, depart on a Saturday or Friday and return on a Thursday
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 November 4, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Popular in | June |
Cheapest in | February |
Average price | $235 |
Cheapflights Insights
Everything you need to know about your flight from San Diego to Boulder
Prices
Airlines
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 November 4, 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 34% on your trip compared to booking a flight in the morning.
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 October 31, 2026.
Travelers seeking maximum savings on their San Diego to Boulder flight should consider departing on Friday evenings when fares are most often at their lowest. Monday afternoons flights should be avoided if possible as fares are typically the most expensive at this time.
Reviews of airlines servicing Boulder
Get insights into the airlines that provide service to Boulder. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Boulder. Reviews last updated November 4, 2026.
See what other customers who have flown with Southwest,Alaska Airlines, andUnited Airlines from San Diego to Boulder have to say. You can also see how each airline compares in terms of entertainment options, comfort, food, crew/service, and boarding process.
Food
7.0
Boarding
8.1
Overall
8.0
Entertainment
7.5
Comfort
8.0
Crew
8.6
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Food
7.0
Boarding
8.1
Overall
8.0
Entertainment
7.5
Comfort
8.0
Crew
8.6
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Food
7.0
Boarding
8.1
Overall
8.0
Entertainment
7.5
Comfort
8.0
Crew
8.6
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Food
7.0
Boarding
8.1
Overall
8.0
Entertainment
7.5
Comfort
8.0
Crew
8.6
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Food
7.0
Boarding
8.1
Overall
8.0
Entertainment
7.5
Comfort
8.0
Crew
8.6
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Food
7.0
Boarding
8.1
Overall
8.0
Entertainment
7.5
Comfort
8.0
Crew
8.6
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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Complete your trip
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Search flights from San Diego to Boulder by cabin class
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San Diego and Boulder flights
Browse other San Diego and Boulder flight options. Last updated on November 4, 2026.
Other flights from San Diego
Browse through other flights departing from San Diego. Flights are based on user searches made on Cheapflights and were last updated on November 4, 2026.
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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 7,457,451 searches. Data last updated November 4, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$47 | Average$152 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$117 | Average$229 | FlexibilityNo cancel fee | On-time75% | |
| Cheapest$117 | Average$313 | FlexibilityNo cancel fee | On-time63% | |
| Cheapest$121 | Average$319 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$133 | Average$203 | FlexibilityNo cancel fee | On-time62% |