Cheap flights from St. Louis to Washington from $108

The month of February is, on average, the cheapest month to fly to State of Washington from St. Louis, with most prices found around $244. If you aren’t able to travel to State of Washington during the month of February, then flying in January is also cheap. Prices for this month can be found on momondo for an average of $292.

The cheapest day to depart from St. Louis to State of Washington is on a Friday. Travelers who choose to depart for State of Washington on a Friday will often find tickets for as low as $485. When flying out on a Monday, the most expensive travel day of the week, you can expect to see flight prices from St. Louis to State of Washington for around $560.

The cheapest time of day to fly to State of Washington is in the evening when flights can be purchased for as low as $471. If you have a flexible travel schedule, then try to avoid flying at noon when prices are $558 on average. Flights to State of Washington from St. Louis at noon are generally more expensive because this time of day is more convenient for travelers’ schedules.

Fly from Lambert-St Louis to Seattle/Tacoma Intl for the best Lambert-St Louis - Washington flight prices

You are more likely to see cheaper flights to State of Washington from St. Louis when booking weeks ahead of your departure date. In general, you can expect to find flights to State of Washington for around $378 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to State of Washington from St. Louis for as low as $331 on momondo.

There are 4 cabin classes available to choose from on St. Louis to State of Washington flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

Delta, United Airlines, and American Airlines are the most popular carriers operating from Lambert-St Louis to Washington

Alaska Airlines, American Airlines and Southwest are the top three most popular airlines that fly to State of Washington from St. Louis according to our data. Alaska Airlines is the first choice among our users, with 68% of people opting to fly with this airline when traveling to State of Washington. Keep in mind that there are 6 different airlines that fly to State of Washington on a routine basis, so you have a few additional options to choose from.

The number of flights available between St. Louis and State of Washington is 2 per day as of November 2026. The most frequent departure time is 6:00AM, with 81% of daily flights leaving at noon.

As of November 2026, 15 flights take off from St. Louis and land in State of Washington each week. The most common flight departure day for this route is Mon, with 47% of weekly flights taking off on this day.