£59 Find Cheap Flights from Seattle to Denver – Compare and Save

Among airlines operating Seattle to Denver flights:

• Frontier: offers free seat selection
• Alaska Airlines: offers extra legroom; offers free seat selection
• United Airlines: offers extra legroom; offers free seat selection
• Delta: offers extra legroom; offers free seat selection
• Southwest: offers free seat selection

Extra legroom and free seat selection availability depends on fare class and route.

6 airlines operate flights between Seattle and Denver. The airlines offering direct flights on this route include:

• United Airlines
• Alaska Airlines
• Southwest
• Delta
• Frontier
• American Airlines

Flights from Seattle to Denver usually depart from Seattle/Tacoma Intl (SEA) and arrive at Denver Intl (DEN).

Here are some options for this route, based on selected ticket types and cabin classes:

• Frontier: a cabin bag and a checked bag in Economy class
• Alaska Airlines: a cabin bag and a checked bag in Economy class
• United Airlines: a cabin bag and a checked bag in Economy class

Bag allowance can vary by ticket type, cabin class, route, and airline, so travellers should check the fare details before booking.

Only Economy class is available on flights from Seattle to Denver.

On this route, stopover flights are cheaper than direct options on average. Stopover fares average £148 return via Ontario (ONT), compared with £185 for direct.

There is no standard. Checked bag policies vary by airline on this route. Most carriers charge £26–£74 for the first checked bag in Economy. Premium fares and elite status bookings typically include a free checked bag.

The Airbus A321neo family is used most often on this route, operated mainly by United Airlines and Frontier. Other aircraft seen on the route include Boeing 737-800 Passenger/BBJ2 (winglets) variants.

Connecting flights from Seattle to Denver most commonly pass through:

• Ontario (ONT) – 58% of one-stop connections
• Salt Lake City (SLC) – 42% of one-stop connections
Together, these airports account for 100% of one-stop bookings on this route.

On the Seattle to Denver route, being flexible with your departure day can save you up to 25%. Saturday is the cheapest day at £173 return on average, while Sunday is the most expensive at £229 – a £56 difference. Cheaper weekend fares like these are typical of routes dominated by weekday business travel.

A flight is considered delayed when it departs 15 minutes or more after its scheduled time. This is the standard used by the US Department of Transportation and most airline industry reporting. On the Seattle to Denver route, 15% of flights were delayed in the past 3 months, with delays averaging 2 hours 23 minutes.

Morning is the busiest departure period on Seattle to Denver flights, with 44% leaving in that window. Afternoon departures account for 38%, Evening flights for 18%, and Night flights for 0%.

Some of the most popular sights in Denver are Colorado Convention Center, Hyatt Regency Denver at Colorado Convention Center, and Coors Field. These are among the most viewed places in Denver on KAYAK.

These are the earliest and latest flight times available from Seattle to Denver:

• Earliest: departs at 05:00 and lands at 07:46
• Latest: departs at 22:00 and lands at 00:46.

The flight takes about 2h 46m.

Last-minute fares on this route (booked within 2 weeks of departure) run 37% above the route average of £185. Book 5 weeks before departure for the lowest fares.

A direct flight from Seattle to Denver takes 2h 46m, covering 1,022 miles.

No, a passport is not required for this domestic route, but you will need a real ID-compliant driver's license, a state ID, or another TSA-accepted form of identification.

Yes. Based on fares seen in the past 5 days, return flight prices on this route showed a wide range, from about £116 to £722. That means the highest observed fare was about 6x higher than the lowest one.

One-way fares from Seattle to Denver are currently lower than usual. Average one-way flight prices are about £70, which is 46% below the typical average for this route.

United Airlines is slightly above the route average for timely arrivals, while Frontier has a lower on-time arrival rate. On-time arrival rates on Seattle to Denver flights are:

• United Airlines: 92% on time
• Frontier: 87% on time
• Alaska Airlines: 85% on time

On average, flights on this route are punctual 85% of the time.

Night flights have the fewest delays on this route. Delays tend to pile up throughout the day as one late flight pushes the next, so earlier departures are usually more reliable.

Flying via Salt Lake City (SLC) gives the shortest average 1-stop total travel time of 7h 38m, compared to 8h 36m via Ontario (ONT).

Denver is 1 hour ahead of Seattle (Mountain Time vs Pacific Time). Plan for the time shift when scheduling connections or first-day activities.

Denver Intl Airport (DEN) hosts 5 major car hire companies, with daily rates starting from around £12 for economy cars. Top options include:
• Routes Car & Truck Rentals
• Ace
• NU Car
• Europcar
• Hertz

Return flights from Seattle to Denver range from £124 to £250, with an average of £185 over the past 12 months. Anything below £124 counts as a good deal.

Three airlines offer in-flight Wi-Fi on Seattle to Denver flights:

• • Alaska Airlines
• • Delta
• • JetBlue