$100 Cheap flight deals from Phoenix (PHX) to Union (STL)

This Weekend's Flight Deals from Phoenix to Union

This weekend's flight prices found within the past 7 days, for the period specified. Prices and availability are subject to change. Additional terms apply.

Sat, Oct 10 - Sat, Oct 17
PHX
Sky Harbor Intl.
STL
Lambert-St. Louis Intl.
$422 Roundtrip, found 2 days ago
$422
Roundtrip
found 2 days ago
Select Frontier Airlines flight, departing Sat, Oct 10 from Sky Harbor Intl. to Lambert-St. Louis Intl., returning Sat, Oct 17, priced at $422 found 2 days ago

Airfares from $100 One Way, $71 Round Trip from Phoenix to Union

Prices starting at $71 for return flights and $100 for one-way flights to Union were the cheapest prices found within the past 7 days, for the period specified. Prices and availability are subject to change. Additional terms apply.

Sat, Nov 7 - Wed, Nov 11
PHX
Phoenix
STL
St. Louis
$71 Roundtrip, found 6 days ago
$71
Roundtrip
found 6 days ago
Select Frontier Airlines flight, departing Sat, Nov 7 from Phoenix to St. Louis, returning Wed, Nov 11, priced at $71 found 6 days ago
Sat, Nov 7 - Wed, Nov 11
PHX
Phoenix
STL
St. Louis
$77 Roundtrip, found 6 days ago
$77
Roundtrip
found 6 days ago
Select Frontier Airlines flight, departing Sat, Nov 7 from Phoenix to St. Louis, returning Wed, Nov 11, priced at $77 found 6 days ago
Sat, Nov 7 - Wed, Nov 11
PHX
Phoenix
STL
St. Louis
$117 Roundtrip, found 6 days ago
$117
Roundtrip
found 6 days ago
Select Frontier Airlines flight, departing Sat, Nov 7 from Phoenix to St. Louis, returning Wed, Nov 11, priced at $117 found 6 days ago
Sat, Nov 7 - Wed, Nov 11
PHX
Phoenix
STL
St. Louis
$122 Roundtrip, found 6 days ago
$122
Roundtrip
found 6 days ago
Select Frontier Airlines flight, departing Sat, Nov 7 from Phoenix to St. Louis, returning Wed, Nov 11, priced at $122 found 6 days ago
Thu, Nov 5 - Fri, Nov 13
PHX
Phoenix
STL
St. Louis
$132 Roundtrip, found 6 days ago
$132
Roundtrip
found 6 days ago
Select Frontier Airlines flight, departing Thu, Nov 5 from Phoenix to St. Louis, returning Fri, Nov 13, priced at $132 found 6 days ago

Union economy flight packages

Price found within the past 48 hours. Click for updated prices.
Moonrise Hotel
4.0-star property

Moonrise Hotel

9/10 Wonderful! (2,026 reviews)

Nov 20 - Nov 22

2 night stay

Phoenix (PHX) to St. Louis (STL)

Southwest Airlines • Coach

St. Louis (STL) to Phoenix (PHX)

Frontier Airlines • Coach
Price was $711, price is now $606 per person
$606
per person
found 5 hours ago
Great family trip great business trip whatever the occasion is it’s amazing

Reviewed on Oct 6, 2026

The Wildwood Hotel
3.5-star property

The Wildwood Hotel

9.2/10 Wonderful! (1,679 reviews)

Nov 20 - Nov 22

2 night stay

Phoenix (PHX) to St. Louis (STL)

Southwest Airlines • Coach

St. Louis (STL) to Phoenix (PHX)

Frontier Airlines • Coach
Price was $858, price is now $613 per person
$613
per person
found 5 hours ago

Ameristar Casino Resort and Spa
4.5-star property

Ameristar Casino Resort and Spa

8.6/10 Excellent! (1,062 reviews)

Nov 20 - Nov 22

2 night stay

Phoenix (PHX) to St. Louis (STL)

Southwest Airlines • Coach

St. Louis (STL) to Phoenix (PHX)

Frontier Airlines • Coach
Price was $781, price is now $690 per person
$690
per person
found 5 hours ago

Don't see what you're looking for?
See all available trips from Phoenix to Union
View all trips

More About Flying To Union from Phoenix