You’d think the 500-mile hop over the Rockies would be a bargain every single time. It’s a short flight. Barely enough time for the flight attendants to hand out a tiny bag of pretzels before the pilot starts the descent into Denver International (DEN). But if you’ve lived in Utah for more than a minute, you know the Salt Lake City International Airport (SLC) can be a fickle beast when it comes to pricing.
One week you’re seeing $56 round-trip tickets on Frontier. The next? Delta wants $400 for a basic economy seat because there’s a convention in town or it’s a holiday weekend. Finding cheap flights from salt lake city to denver colorado isn't just about luck. It’s about knowing which airlines are actually fighting for your business and when to pull the trigger.
Honestly, people overcomplicate this. They wait for "Tuesday at midnight" to book because they heard that once in 2014. It doesn't work like that anymore.
The Budget King vs. The Big Three
Frontier Airlines is basically the reason this route stays affordable for the rest of us. They are the "hometown hero" in Denver, and they run a high-frequency shuttle service from SLC. Right now, you can regularly find one-way fares for $25 to $29 if you’re traveling on a random Wednesday in February or March.
But there is a massive catch.
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If you bring anything larger than a school backpack, Frontier will charge you more for the bag than the flight itself. I’ve seen people pay $75 at the gate because their "personal item" had wheels. If you need a carry-on, suddenly that $29 fare is $100.
That’s where Southwest comes in. Southwest is the secret weapon for this specific route. They usually offer about 7 nonstop flights a day on weekdays. While their base fare might look higher—say $135 round-trip—you get two checked bags for free. If you’re heading to Colorado for a ski weekend and need to bring your own gear, Southwest wins every single time. No contest.
Then you have Delta and United. They both treat SLC and DEN as major hubs. They’re great for reliability, but you’re going to pay a "hub premium" unless you book at least 21 days out.
Quick Price Reality Check (Typical 2026 Rates)
- Frontier: $55–$145 (Watch the bag fees!)
- Southwest: $135–$280 (Includes 2 bags)
- United/Delta: $140–$300 (Best for loyalty points)
Timing the Mountain West Market
The cheapest month to fly from Salt Lake City to Denver is almost always February. Why? Because the holiday rush is over, and while it's prime ski season, the mid-week doldrums hit the airlines hard.
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Avoid Sundays. Seriously.
Sunday is the most expensive day to fly this route. Everyone is trying to get back for work on Monday. If you can fly on a Tuesday or Wednesday, you’ll usually save about 30% compared to a Friday-Sunday itinerary. According to recent 2026 data, booking on a Sunday (the day you actually buy the ticket) can also snag you a price that's about 10% lower than if you bought it on a Friday.
The "Hidden" Costs of Denver International
Don't forget that landing in Denver is only half the battle. DEN is notoriously far from the actual city of Denver. It's basically in Kansas.
If you find a "cheap" flight that lands at 11:00 PM, a rideshare to downtown can easily cost you $50 to $70. Suddenly, your $28 Frontier flight just cost you a hundred bucks.
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Pro tip: Take the A-Line train from the airport to Union Station. It’s about $10.50 and takes 37 minutes. It’s way cheaper than an Uber and you don't have to deal with the soul-crushing traffic on I-70.
Is Driving Actually Better?
It’s about 8 hours. 530 miles.
If you have a car that gets decent gas mileage, driving is cheaper if you have three or more people. But for a solo traveler? Between the gas and the wear and tear, flying usually wins—especially when you consider that a flight is only 1 hour and 30 minutes of air time.
How to actually snag the deal
Don't just stare at Google Flights. Use the "Track Prices" toggle. Set it and forget it. You'll get an email the second United decides to match a Frontier sale.
Also, look at "Hacker Fares." This is basically booking your outbound flight on Frontier and your return on Southwest. It’s a bit of extra work because you’ll have two different confirmation numbers, but it can save you $40 or $50 on a weekend trip.
Actionable Steps for Your Next Trip:
- Check the Southwest Low Fare Calendar first. Since their prices don't show up on Google Flights or Expedia, most people miss their best deals.
- Pack in a small backpack. If you can fit everything into a 18x14x8 inch bag, Frontier will be your cheapest option by a landslide.
- Fly mid-week. Tuesday and Wednesday are the "golden days" for the SLC-DEN route.
- Download the RTD MyRide app. Have your train fare ready for when you land in Denver so you aren't stuck waiting 20 minutes for a $60 Uber.
- Book 3-4 weeks out. This isn't a route where "last minute" usually works out in your favor unless you're flying on a Tuesday.
Focus on these specific moves and you'll stop overpaying for a flight that’s shorter than a movie. If you’re flexible, there is no reason to ever pay more than $150 for a round-trip ticket between these two cities.