Cheap flights from Portland to St. Louis from $126

In general, November is the cheapest month to fly from Portland to St. Louis. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $302. The month of May is another great option to travel to St. Louis, with average flight prices from Portland averaging around $318.

The cheapest day to depart on your flight to St. Louis is on a Friday when prices can be found for as low as $329. This is often the case because there is less demand to fly during this day of the week. If your travel schedule is flexible, try to avoid departing on a Sunday because tickets tend to average around $518. These prices are subject to change though, so be sure to set up a Price Alert for flights to St. Louis.

Flying to St. Louis from Portland in the morning is the least expensive time of day to depart. momondo users have found prices as low as $388 when looking at flights departing in the morning. At noon is when there is more demand to fly to St. Louis, so prices are often more expensive at around $679 per ticket.

Fly from Portland to Lambert-St Louis for the best Portland - Lambert-St Louis flight prices

You are more likely to see cheaper flights to St. Louis from Portland when booking weeks ahead of your departure date. In general, you can expect to find flights to St. Louis for around $375 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to St. Louis from Portland for as low as $240 on momondo.

There are 2 cabin classes available to choose from on Portland to St. Louis flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

No. A direct flight is the cheapest option for a flight between Portland to St. Louis.

As of June 2026, prices for Portland to St. Louis flights are approximately 51% more expensive when compared to flights at the same time last year.

Delta and Southwest are the most popular carriers operating from Portland to Lambert-St Louis

Delta, Alaska Airlines and United Airlines are the top three most popular airlines that fly to St. Louis from Portland according to our data. Delta is the first choice among our users, with 32% of people opting to fly with this airline when traveling to St. Louis. Keep in mind that there are 6 different airlines that fly to St. Louis on a routine basis, so you have a few additional options to choose from.

Denver (DEN) was the most common stop: 75% of momondo users choosing 1-stop flights on this route connected there.

Flights via Minneapolis (MSP) offer the lowest average round-trip price of $249.

Flights connecting via Denver (DEN) have the shortest average one-way travel time: 5h 48m.

Denver (DEN) has the shortest average layover time for this route: 1h 09m.

1 flights are operational daily from Portland to St. Louis as of June 2026. The most popular departure time for this route is 10:00AM, with 100% of flights per day taking off at noon.

The number of flights available between Portland and St. Louis is 7 per week as of June 2026. The most frequent departure day is Mon, with 14% of weekly flights leaving on this day.