Flights from St. Louis to Union

Cheapest flights from St. Louis

These prices were available within the past 7 days. Prices quoted are per person, round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Tue, Jun 10 - Fri, Jun 13

STL

Lambert-St. Louis Intl.

SEA

Seattle - Tacoma Intl.

$167 Roundtrip, found 4 days ago

$167

Roundtrip

found 4 days ago

Select American Airlines flight, departing Tue, Jun 10 from Lambert-St. Louis Intl. to Seattle - Tacoma Intl., returning Fri, Jun 13, priced at $167 found 4 days ago

Tue, Jun 10 - Fri, Jun 13

STL

Lambert-St. Louis Intl.

SEA

Seattle - Tacoma Intl.

$168 Roundtrip, found 4 days ago

$168

Roundtrip

found 4 days ago

Select American Airlines flight, departing Tue, Jun 10 from Lambert-St. Louis Intl. to Seattle - Tacoma Intl., returning Fri, Jun 13, priced at $168 found 4 days ago

Tue, Jun 10 - Fri, Jun 13

STL

Lambert-St. Louis Intl.

SEA

Seattle - Tacoma Intl.

$176 Roundtrip, found 4 days ago

$176

Roundtrip

found 4 days ago

Select Delta flight, departing Tue, Jun 10 from Lambert-St. Louis Intl. to Seattle - Tacoma Intl., returning Fri, Jun 13, priced at $176 found 4 days ago

Mon, Jun 30 - Wed, Jul 9

STL

Lambert-St. Louis Intl.

SEA

Seattle - Tacoma Intl.

$177 Roundtrip, found 3 days ago

$177

Roundtrip

found 3 days ago

Select Delta flight, departing Mon, Jun 30 from Lambert-St. Louis Intl. to Seattle - Tacoma Intl., returning Wed, Jul 9, priced at $177 found 3 days ago

Sun, Jun 29 - Wed, Jul 9

STL

Lambert-St. Louis Intl.

SEA

Seattle - Tacoma Intl.

$183 Roundtrip, found 3 days ago

$183

Roundtrip

found 3 days ago

Select Delta flight, departing Sun, Jun 29 from Lambert-St. Louis Intl. to Seattle - Tacoma Intl., returning Wed, Jul 9, priced at $183 found 3 days ago

Tue, Sep 9 - Tue, Sep 23

STL

Lambert-St. Louis Intl.

SEA

Seattle - Tacoma Intl.

$189 Roundtrip, found 5 hours ago

$189

Roundtrip

found 5 hours ago

Select Delta flight, departing Tue, Sep 9 from Lambert-St. Louis Intl. to Seattle - Tacoma Intl., returning Tue, Sep 23, priced at $189 found 5 hours ago

Tue, Jun 10 - Fri, Jun 13

STL

Lambert-St. Louis Intl.

SEA

Seattle - Tacoma Intl.

$196 Roundtrip, found 4 days ago

$196

Roundtrip

found 4 days ago

Select United flight, departing Tue, Jun 10 from Lambert-St. Louis Intl. to Seattle - Tacoma Intl., returning Fri, Jun 13, priced at $196 found 4 days ago

Wed, Jun 11 - Thu, Jun 12

STL

Lambert-St. Louis Intl.

SEA

Seattle - Tacoma Intl.

$197 Roundtrip, found 4 days ago

$197

Roundtrip

found 4 days ago

Select Delta flight, departing Wed, Jun 11 from Lambert-St. Louis Intl. to Seattle - Tacoma Intl., returning Thu, Jun 12, priced at $197 found 4 days ago

Tue, Jun 10 - Mon, Jun 16

STL

Lambert-St. Louis Intl.

SEA

Seattle - Tacoma Intl.

$198 Roundtrip, found 4 days ago

$198

Roundtrip

found 4 days ago

Select Delta flight, departing Tue, Jun 10 from Lambert-St. Louis Intl. to Seattle - Tacoma Intl., returning Mon, Jun 16, priced at $198 found 4 days ago

Thu, Jul 3 - Wed, Jul 9

STL

Lambert-St. Louis Intl.

SEA

Seattle - Tacoma Intl.

$208 Roundtrip, found 3 days ago

$208

Roundtrip

found 3 days ago

Select Delta flight, departing Thu, Jul 3 from Lambert-St. Louis Intl. to Seattle - Tacoma Intl., returning Wed, Jul 9, priced at $208 found 3 days ago

Tue, Jun 10 - Fri, Jun 13

STL

Lambert-St. Louis Intl.

SEA

Seattle - Tacoma Intl.

$209 Roundtrip, found 4 days ago

$209

Roundtrip

found 4 days ago

Select American Airlines flight, departing Tue, Jun 10 from Lambert-St. Louis Intl. to Seattle - Tacoma Intl., returning Fri, Jun 13, priced at $209 found 4 days ago

Tue, Jun 10 - Fri, Jun 13

STL

Lambert-St. Louis Intl.

SEA

Seattle - Tacoma Intl.

$212 Roundtrip, found 4 days ago

$212

Roundtrip

found 4 days ago

Select American Airlines flight, departing Tue, Jun 10 from Lambert-St. Louis Intl. to Seattle - Tacoma Intl., returning Fri, Jun 13, priced at $212 found 4 days ago

Tue, Jun 10 - Fri, Jun 13

STL

Lambert-St. Louis Intl.

SEA

Seattle - Tacoma Intl.

$213 Roundtrip, found 4 days ago

$213

Roundtrip

found 4 days ago

Select American Airlines flight, departing Tue, Jun 10 from Lambert-St. Louis Intl. to Seattle - Tacoma Intl., returning Fri, Jun 13, priced at $213 found 4 days ago

Wed, Jun 11 - Mon, Jun 16

STL

Lambert-St. Louis Intl.

SEA

Seattle - Tacoma Intl.

$218 Roundtrip, found 4 days ago

$218

Roundtrip

found 4 days ago

Select Delta flight, departing Wed, Jun 11 from Lambert-St. Louis Intl. to Seattle - Tacoma Intl., returning Mon, Jun 16, priced at $218 found 4 days ago

Tue, Jun 10 - Fri, Jun 13

STL

Lambert-St. Louis Intl.

SEA

Seattle - Tacoma Intl.

$221 Roundtrip, found 4 days ago

$221

Roundtrip

found 4 days ago

Select Delta flight, departing Tue, Jun 10 from Lambert-St. Louis Intl. to Seattle - Tacoma Intl., returning Fri, Jun 13, priced at $221 found 4 days ago

Tue, Jun 10 - Fri, Jun 13

STL

Lambert-St. Louis Intl.

SEA

Seattle - Tacoma Intl.

$227 Roundtrip, found 4 days ago

$227

Roundtrip

found 4 days ago

Select United flight, departing Tue, Jun 10 from Lambert-St. Louis Intl. to Seattle - Tacoma Intl., returning Fri, Jun 13, priced at $227 found 4 days ago

Sat, Jun 7 - Tue, Jun 10

STL

Lambert-St. Louis Intl.

SEA

Seattle - Tacoma Intl.

$229 Roundtrip, found 4 days ago

$229

Roundtrip

found 4 days ago

Select Frontier Airlines flight, departing Sat, Jun 7 from Lambert-St. Louis Intl. to Seattle - Tacoma Intl., returning Tue, Jun 10, priced at $229 found 4 days ago

Tue, Sep 9 - Thu, Sep 25

STL

Lambert-St. Louis Intl.

SEA

Seattle - Tacoma Intl.

$249 Roundtrip, found 5 hours ago

$249

Roundtrip

found 5 hours ago

Select Hawaiian Airlines flight, departing Tue, Sep 9 from Lambert-St. Louis Intl. to Seattle - Tacoma Intl., returning Thu, Sep 25, priced at $249 found 5 hours ago

Tue, Jun 10 - Fri, Jun 13

STL

Lambert-St. Louis Intl.

SEA

Seattle - Tacoma Intl.

$268 Roundtrip, found 4 days ago

$268

Roundtrip

found 4 days ago

Select United flight, departing Tue, Jun 10 from Lambert-St. Louis Intl. to Seattle - Tacoma Intl., returning Fri, Jun 13, priced at $268 found 4 days ago

Tue, Jun 10 - Fri, Jun 13

STL

Lambert-St. Louis Intl.

SEA

Seattle - Tacoma Intl.

$333 Roundtrip, found 4 days ago

$333

Roundtrip

found 4 days ago

Select Alaska Airlines flight, departing Tue, Jun 10 from Lambert-St. Louis Intl. to Seattle - Tacoma Intl., returning Fri, Jun 13, priced at $333 found 4 days ago