AirHint found the following cheapest return flights from Phoenix (PHX) to Riga (RIX) in September 2025 (see full year).

Return flights

27 Sep - 14 Oct	Frontier Airlines
26 Sep - 16 Oct	Frontier Airlines
27 Sep - 16 Oct	Frontier Airlines
24 Sep - 16 Oct	Frontier Airlines
27 Sep - 15 Oct	Frontier Airlines
25 Sep - 16 Oct	Frontier Airlines
21 Sep - 15 Oct	Frontier Airlines
23 Sep - 16 Oct	Frontier Airlines
22 Sep - 16 Oct	Frontier Airlines

Also check the deals for one-way flights from Phoenix to Riga in September.

The deals are updated regularly. The prices may go up as tickets are purchased by other travellers. Only the cheapest flights are offered. Select a price to book and secure these cheap prices.

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Cheapest return flights from Phoenix to Riga in September from $790

Return flights