$198 Cheap Flights from San Francisco (SFO) to Sidney (SDY)

View $198 flight on Fri, Jan 23, 2026Opens in a new window

Popular airlines from San Francisco Intl. Airport (SFO) to Sidney, MT (SDY-Sidney-Richland Municipal)

Cheap Flights from San Francisco to Sidney (SFO-SDY)

Prices were available within the past 7 days and start at $198 for one-way flights and $376 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

United
Sat, Jan 17 - Sat, Jan 24
SFO
San Francisco
SDY
Sidney
$376 Roundtrip, found 2 days ago
$376
Roundtrip
found 2 days ago
Select United flight, departing Sat, Jan 17 from San Francisco to Sidney, returning Sat, Jan 24, priced at $376 found 2 days ago
Alaska Airlines
Sat, Jan 17 - Sat, Jan 24
SFO
San Francisco
SDY
Sidney
$385 Roundtrip, found 2 days ago
$385
Roundtrip
found 2 days ago
Select Alaska Airlines flight, departing Sat, Jan 17 from San Francisco to Sidney, returning Sat, Jan 24, priced at $385 found 2 days ago
Alaska Airlines
Fri, Jan 16 - Wed, Jan 21
SFO
San Francisco
SDY
Sidney
$395 Roundtrip, found 2 days ago
$395
Roundtrip
found 2 days ago
Select Alaska Airlines flight, departing Fri, Jan 16 from San Francisco to Sidney, returning Wed, Jan 21, priced at $395 found 2 days ago
Delta
Thu, Jan 1 - Fri, Feb 13
SFO
San Francisco
SDY
Sidney
$401 Roundtrip, found 3 days ago
$401
Roundtrip
found 3 days ago
Select Delta flight, departing Thu, Jan 1 from San Francisco to Sidney, returning Fri, Feb 13, priced at $401 found 3 days ago
Hawaiian Airlines
Fri, Jan 16 - Thu, Jan 22
SFO
San Francisco
SDY
Sidney
$405 Roundtrip, found 2 days ago
$405
Roundtrip
found 2 days ago
Select Hawaiian Airlines flight, departing Fri, Jan 16 from San Francisco to Sidney, returning Thu, Jan 22, priced at $405 found 2 days ago
United
Sat, Jan 17 - Sat, Jan 24
SFO
San Francisco
SDY
Sidney
$416 Roundtrip, found 2 days ago
$416
Roundtrip
found 2 days ago
Select United flight, departing Sat, Jan 17 from San Francisco to Sidney, returning Sat, Jan 24, priced at $416 found 2 days ago
Hawaiian Airlines
Thu, Jan 15 - Fri, Jan 23
SFO
San Francisco
SDY
Sidney
$425 Roundtrip, found 2 days ago
$425
Roundtrip
found 2 days ago
Select Hawaiian Airlines flight, departing Thu, Jan 15 from San Francisco to Sidney, returning Fri, Jan 23, priced at $425 found 2 days ago
Alaska Airlines
Sat, Jan 17 - Sat, Jan 24
SFO
San Francisco
SDY
Sidney
$432 Roundtrip, found 2 days ago
$432
Roundtrip
found 2 days ago
Select Alaska Airlines flight, departing Sat, Jan 17 from San Francisco to Sidney, returning Sat, Jan 24, priced at $432 found 2 days ago
Hawaiian Airlines
Thu, Jan 15 - Sun, Jan 25
SFO
San Francisco
SDY
Sidney
$435 Roundtrip, found 2 days ago
$435
Roundtrip
found 2 days ago
Select Hawaiian Airlines flight, departing Thu, Jan 15 from San Francisco to Sidney, returning Sun, Jan 25, priced at $435 found 2 days ago
Alaska Airlines
Sat, Jan 17 - Sat, Jan 24
SFO
San Francisco
SDY
Sidney
$447 Roundtrip, found 2 days ago
$447
Roundtrip
found 2 days ago
Select Alaska Airlines flight, departing Sat, Jan 17 from San Francisco to Sidney, returning Sat, Jan 24, priced at $447 found 2 days ago

Alternative airports near Sidney

Prices were available within the past 7 days. Prices and availability are subject to change.

Select flight to Sidney-Richland Municipal SDY. Cheapest and Closest option available. Average driving time to city center is 3 minutes. Flights from $1,132
SDY
Sidney-Richland Municipal
CheapestClosest
Average driving time to city center3 min
Flights from $1,132
Flights from San Francisco (SFO) to Sidney (SDY)
Origin airport
San Francisco Intl.
Destination airport
Sidney-Richland Municipal
Roundtrip price
$375
Distance
1153 mi

San Francisco to Sidney Flights

The cheapest times to fly from San Francisco to Sidney

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 San Francisco to Sidney are during the month of January. You can find some of the cheapest flights from San Francisco to Sidney with Expedia's search tool and vast selection of airlines.

 

The best time to book a flight from San Francisco to Sidney

Sunday is one of the best days to book for cheap flights from San Francisco to Sidney: 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 San Francisco to Sidney

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 San Francisco to Sidney in 2026. You can also book with separate airlines for your outbound and return journeys, from $198 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 San Francisco to Sidney 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 San Francisco to Sidney 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 San Francisco Intl. Airport (SFO) to Sidney-Richland Municipal Airport (SDY) cost?
Lock in a cheap one-way flight from $198 or cheap return flight from $376 from San Francisco Intl. Airport (SFO) to Sidney-Richland Municipal Airport (SDY) with Expedia. Enter your travel dates and sort by "Price (lowest to highest)" to see our cheapest flight offers on this route.
What is the cheapest month to fly from San Francisco Intl. Airport (SFO) to Sidney-Richland Municipal Airport (SDY)?
Traveling in January is a great way to save, as it's the cheapest month for flights between SFO and SDY. You'll often find the lowest prices during off-peak months.
What is the cheapest airline that flies from San Francisco Intl. Airport (SFO) to Sidney-Richland Municipal Airport (SDY)?
To find the cheapest airline flying from SFO to SDY, use Expedia's filter tool. Customize your search based on your travel style, such as preferred carriers and number of stops. You can then sort your results by "Price (lowest to highest)" to see the cheapest flights first.
How many flights per day from San Francisco Intl. Airport (SFO) to Sidney-Richland Municipal Airport (SDY)?
You'll need to book a flight with a layover when traveling from San Francisco Intl. Airport (SFO) to Sidney-Richland Municipal Airport (SDY). Direct flights don't operate daily on this route. However, simply filter your search to include one or more stops to discover an option that works for you.
What day of the week has the most flights from SFO to SDY?
You'll generally find Tuesday the quietest day for flights, while Fridays are often the busiest.* However this can change from season to season and during peak travel times or public holidays.*Busiest/quietest day to travel is based on Expedia flight demand through January to December 2024.
What is the best time to fly from San Francisco Intl. Airport (SFO) to Sidney-Richland Municipal Airport (SDY)?
Book a flight from San Francisco Intl. Airport (SFO) to Sidney-Richland Municipal Airport (SDY) that leaves before 3 PM to reduce the risk of delays and cancellations. Departures later than this are on average 22% more likely to be canceled.**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 San Francisco Intl. Airport (SFO) to Sidney-Richland Municipal Airport (SDY) last-minute?
Waiting until just before your departure to book your flight from SFO to SDY often results in higher prices. While you might find some last-minute deals, they're not always guaranteed. Allow some flexibility in your schedule for a better chance of landing a bargain.
Is it cheaper to book a SFO to SDY flight and hotel package?
You'll generally save money by booking a SFO to SDY flight and hotel package compared to booking separately. In fact, you could save hundreds of dollars by bundling with Expedia. And it's simple to manage it all in one convenient place. After choosing your ideal accommodations and flights, you can add extras like car rentals, activities and tours.
Can I cancel or change the date of my flight from San Francisco Intl. Airport (SFO) to Sidney-Richland Municipal Airport (SDY)?
It's usually possible to reschedule or cancel your SFO to SDY flight. However, if the booking was made more than 24 hours ago, additional fees may apply. Refer to your airline's policies in your itinerary to see what changes are allowed and if any costs are involved. You'll also find more details on our Customer Service portal.

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*Available to One Key members.