$263 Cheap Flights from Helena (HLN) to Santa Rosa (STS)

View $263 flight on Fri, Oct 10, 2025Opens in a new window

Popular airlines from Helena, MT (HLN-Helena Regional) to Santa Rosa, CA (STS-Sonoma County)

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Cheap Flights from Helena to Santa Rosa (HLN-STS)

Prices were available within the past 7 days and start at $263 for one-way flights and $760 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Alaska Airlines
Mon, Aug 18 - Fri, Aug 22
HLN
Helena
STS
Santa Rosa
$760 Roundtrip, found 4 days ago
$760
Roundtrip
found 4 days ago
Select Alaska Airlines flight, departing Mon, Aug 18 from Helena to Santa Rosa, returning Fri, Aug 22, priced at $760 found 4 days ago
Alaska Airlines
Mon, Aug 18 - Fri, Aug 22
HLN
Helena
STS
Santa Rosa
$797 Roundtrip, found 4 days ago
$797
Roundtrip
found 4 days ago
Select Alaska Airlines flight, departing Mon, Aug 18 from Helena to Santa Rosa, returning Fri, Aug 22, priced at $797 found 4 days ago
Alaska Airlines
Mon, Aug 18 - Fri, Aug 22
HLN
Helena
STS
Santa Rosa
$830 Roundtrip, found 4 days ago
$830
Roundtrip
found 4 days ago
Select Alaska Airlines flight, departing Mon, Aug 18 from Helena to Santa Rosa, returning Fri, Aug 22, priced at $830 found 4 days ago
Hawaiian Airlines
Mon, Aug 11 - Thu, Aug 14
HLN
Helena
STS
Santa Rosa
$1,143 Roundtrip, found 5 hours ago
$1,143
Roundtrip
found 5 hours ago
Select Hawaiian Airlines flight, departing Mon, Aug 11 from Helena to Santa Rosa, returning Thu, Aug 14, priced at $1,143 found 5 hours ago
Hawaiian Airlines
Mon, Aug 11 - Wed, Aug 13
HLN
Helena
STS
Santa Rosa
$1,173 Roundtrip, found 5 hours ago
$1,173
Roundtrip
found 5 hours ago
Select Hawaiian Airlines flight, departing Mon, Aug 11 from Helena to Santa Rosa, returning Wed, Aug 13, priced at $1,173 found 5 hours ago
Hawaiian Airlines
Tue, Aug 12 - Thu, Aug 14
HLN
Helena
STS
Santa Rosa
$1,183 Roundtrip, found 5 hours ago
$1,183
Roundtrip
found 5 hours ago
Select Hawaiian Airlines flight, departing Tue, Aug 12 from Helena to Santa Rosa, returning Thu, Aug 14, priced at $1,183 found 5 hours ago
Hawaiian Airlines
Mon, Aug 11 - Sat, Aug 16
HLN
Helena
STS
Santa Rosa
$1,193 Roundtrip, found 5 hours ago
$1,193
Roundtrip
found 5 hours ago
Select Hawaiian Airlines flight, departing Mon, Aug 11 from Helena to Santa Rosa, returning Sat, Aug 16, priced at $1,193 found 5 hours ago
Hawaiian Airlines
Tue, Aug 12 - Sat, Aug 16
HLN
Helena
STS
Santa Rosa
$1,208 Roundtrip, found 5 hours ago
$1,208
Roundtrip
found 5 hours ago
Select Hawaiian Airlines flight, departing Tue, Aug 12 from Helena to Santa Rosa, returning Sat, Aug 16, priced at $1,208 found 5 hours ago
Hawaiian Airlines
Tue, Aug 12 - Wed, Aug 13
HLN
Helena
STS
Santa Rosa
$1,214 Roundtrip, found 5 hours ago
$1,214
Roundtrip
found 5 hours ago
Select Hawaiian Airlines flight, departing Tue, Aug 12 from Helena to Santa Rosa, returning Wed, Aug 13, priced at $1,214 found 5 hours ago
Delta
Sun, Aug 10 - Thu, Aug 14
HLN
Helena
STS
Santa Rosa
$1,361 Roundtrip, found 5 hours ago
$1,361
Roundtrip
found 5 hours ago
Select Delta flight, departing Sun, Aug 10 from Helena to Santa Rosa, returning Thu, Aug 14, priced at $1,361 found 5 hours ago
Flights from Helena (HLN) to Santa Rosa (STS)
Origin airport
Helena Regional
Destination airport
Sonoma County
Roundtrip price
$759
Distance
783 mi

Helena to Santa Rosa Flights

The cheapest times to fly from Helena to Santa Rosa

On average, Thursday can be the cheapest time to fly, according to data from the Airlines Reporting Corporation (ARC), one of the world's biggest databases for global airline sales. The data reveals that you could save up to 16% by flying on a Thursday—the cheapest day to travel on average—instead of a Sunday—the most expensive. Some of the most affordable flights from Helena to Santa Rosa are during the month of August. You can find some of the cheapest flights from Helena to Santa Rosa with Expedia's search tool and vast selection of airlines.

 

The best time to book a flight from Helena to Santa Rosa

Sunday is one of the best days to book for cheap flights from Helena to Santa Rosa: Tickets reserved on a Sunday cost between 6% and 13% less than those reserved on a Friday, according to ARC data. The data also suggests booking early can also lead to cheaper airfares. You could save 24% by buying your tickets for domestic flights at least a month in advance and 10% by booking international flights 2 months in advance.

 

How to find cheap round-trip tickets from Helena to Santa Rosa

Being flexible with your dates and using Expedia's Price Drop Protection and Price Tracking features are some of the best ways of finding a cheap ticket from Helena to Santa Rosa in 2025. You can also book with separate airlines for your outbound and return journeys, from $263 one-way. Expedia also offers Price Drop Protection, so if the cost of your airfare goes down after booking, you'll receive a credit for the difference*. This is available for a small fee, and is free to One Key Gold and Platinum tier members.

 

Expedia's Price Tracking feature means you can stay on top of airfares without manually checking every day. It sends you automated price alerts for cheap Helena to Santa Rosa flights and uses historical data to indicate when the best time to book is. Download Expedia's free app to activate this handy tool in a few easy taps.

 

You could also save big by booking one of Expedia's vacation packages. Bundling together your Helena to Santa Rosa airfare with your accommodations and car rental is often cheaper than booking everything separately. There’s also One Key, Expedia's generous rewards program. Join for free and you could earn One Key cash on most bookings to save on future adventures.

 

*Terms apply.

 

Disclaimer: ARC The statistics are based on average round-trip ticket prices between January and August 2023. The percentages you see are averages.

 

Frequently asked questions

How much does a flight from Helena Regional Airport (HLN) to Sonoma County Airport (STS) cost?
Grab a cheap one-way flight from $263 or cheap return flight from $760 from Helena Regional Airport (HLN) to Sonoma County Airport (STS) with Expedia. Enter your travel dates and sort by "Price (lowest to highest)" to find our cheapest flight offers on this route.
What is the cheapest month to fly from Helena Regional Airport (HLN) to Sonoma County Airport (STS)?
The cheapest month to fly from HLN to STS is August, when there's less demand. Off-peak season is generally when you'll find lower airfares between these airports.
What is the cheapest airline that flies from Helena Regional Airport (HLN) to Sonoma County Airport (STS)?
To find the cheapest airline flying from HLN to STS, use Expedia's filter tool. Tailor your search based on your travel needs, such as preferred carriers and ideal departure window. You can then sort your results by "Price (lowest to highest)" to list the most affordable options first.
How many flights per day from Helena Regional Airport (HLN) to Sonoma County Airport (STS)?
There are no daily direct flights departing from Helena Regional Airport (HLN) to Sonoma County Airport (STS). But you can book flights with layovers. Filter your search on Expedia to include one or more stops, and you'll be soaring above the clouds before you know it.
What day of the week has the most flights from HLN to STS?
Generally you'll have the most choice when it comes to flights on a Friday. Tuesdays tend to be the quietest.* However, this can vary based on the time of year, airline and other factors.*Busiest/quietest day to travel is based on Expedia flight demand through January to December 2024.
What is the best time to fly from Helena Regional Airport (HLN) to Sonoma County Airport (STS)?
To land at Sonoma County Airport (STS) on schedule, book a flight that leaves from Helena Regional Airport (HLN) before 3 PM. The likelihood of cancellations is 22% higher, on average, for departures after this hour.**Most reliable time of the day and month to travel recommendation is based on January through August 2024 flight status data sourced from OAG's global flight data platform.
Is it cheaper to buy a plane ticket from Helena Regional Airport (HLN) to Sonoma County Airport (STS) last-minute?
Waiting until right before your break to book a flight from HLN to STS often results in higher prices. While you might find some last-minute discounts, they're not always guaranteed. Keep your travel schedule open for a better chance of snagging a bargain.
Is it cheaper to book a HLN to STS flight and hotel package?
Compared with arranging flights and hotels separately, booking a HLN to STS flight and hotel package with Expedia could lead to significant savings. Better still, having everything in one convenient place takes the hassle out of planning your trip. Simply secure your flights and choose from our wide range of hotels, then personalize your trip with other add-ons like activities, tours and car rentals.
Can I cancel or change the date of my flight from Helena Regional Airport (HLN) to Sonoma County Airport (STS)?
Typically, you're able to cancel or reschedule your HLN to STS flight. However, additional charges may apply, especially if your booking was made more than 24 hours ago. Double-check your itinerary for the airline's fees and policies on flight changes, or if you need more details, head to our Customer Service portal.

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*Available to One Key members.