The cheapest times to fly from STL to IDA are

  • April 16th to April 29th
  • August 13th to March 4th (except the weeks of November 19th, November 26th, December 17th, December 24th, and February 12th)

based on data collected exclusively by Champion Traveler across tens of millions of flights. Among all the dates above, the very cheapest time to fly from STL to IDA is early November. Prices can be as high as $906 for Sunday flights during early to mid May, or as low as $308 for Tuesday flights around early November.


When to Fly to Idaho Falls

Flying from St. Louis, MO (STL) to Idaho Falls, ID (IDA) will usually cost between $311 to $675 per person if booking more than four weeks in advance. On average the very cheapest time to fly is early November with an average ticket price of $347. Due to high demand the most expensive time to fly is early to mid May, with an average price of $612. Planning your trip to low-cost times can easily save you $266 on economy flights and even more on first-class flights. Generally, any price below $457 can be considered a good price for a round-trip STL to IDA flight.

See below for a graph of average weekly prices for the STL to IDA route. All prices are for round-trip tickets in USD.

STL to IDA Flight Prices

Compared to other flights, the STL to IDA flight is much cheaper than the average and costs much less than the average flight leaving from St. Louis. The average price per mile (for a direct flight) is $0.24, which is below average.


Flight Prices by Day of the Week

Tuesday is usually the cheapest day to depart and return on this flight. Sundays are the most expensive days to fly out or take a return trip. Selecting flights on the least expensive days could save you up to $183 (33%) on this flight.

Departing prices are for round-trip flights returning on the day of departure. For example, a flight departing on Tuesday and returning a week later will cost an average of $368. Return trip prices are from the IDA to STL flight, and often highlight the quality of our data in showing the same trend.

Departing Prices by Day

Departure Day Prices

Return Trip Prices by Day

Return Day Prices


Nonstop Flights and Layovers

Travelers looking to fly from STL to IDA can generally find a 1-layover flight. Because there is not usually a direct flight option the real-world direct flight time of 3 hour 5 minutes may not be realistic.


Alternative Nearby Airports

Champion Traveler tells you which airports are nearby and whether tickets might be cheaper alternative airports nearby. Sometimes it’s worth it to fly into a closer airport and then commute to your destination. Remember that there is not usually a nonstop flight from STL to IDA while comparing.

Destination alternative #1: Joslin Field – Magic Valley Regional Airport (TWF) in Twin Falls, ID

  • 141 miles (227 km) away from IDA
  • Usually 19.04% less expensive than IDA
  • 1-layover flights available

See STL to TWF flights

Destination alternative #2: Pocatello Regional Airport (PIH) in Pocatello, ID

  • 49 miles (79 km) away from IDA
  • Usually 16.74% less expensive than IDA
  • 1-layover flights available

See STL to PIH flights

Destination alternative #3: Friedman Memorial Airport (SUN) in Sun Valley/Hailey/Ketchum, ID

  • 112 miles (180 km) away from IDA
  • Usually 6.13% less expensive than IDA
  • 1-layover flights available

See STL to SUN flights


Flight Questions Answered

Still have questions about flying from STL to IDA? We’ve got answers.

Which airlines fly this route?

You can find 4 major airlines flying this route most often: Alaska, Cape Air, Delta, United, and potentially more during busy seasons.

How far away is it from Idaho Falls Regional Airport to St Louis Lambert International Airport?

The distance between the two airports is roughly 1172 miles or 1886 kilometers.

How long does it take to fly from STL to IDA?

The real-world flight time for a nonstop STL to IDA flight is about 3 hour 5 minutes.

How many flights go between St. Louis, MO and Idaho Falls, ID?

It depends on the day of the week and the date, but a typical day might have around 47 available flights from STL to IDA.


Airport Location Info


Departing Airport

Origination code STL
Origination airport name St Louis Lambert International Airport
City St. Louis, MO
Country the United States
Latitude 38.7
Longitude -90.4

Return Airport

Destination code IDA
Destination airport name Idaho Falls Regional Airport
City Idaho Falls, ID
Country the United States
Latitude 43.5
Longitude -112.1


Other Resources

Please note that while we’ve worked hard to analyzed tens of millions of flights to get you this data, we do not calculate current live prices or guarantee pricing. Please see our partners using the links above for current offers.