AirHint found the following cheapest one-way flights from Portland (PDX) to San Francisco (SFO) in August 2025 (see full year).

One-Way flights

25 Aug	Frontier Airlines
26 Aug	Frontier Airlines
23 Aug	Frontier Airlines
27 Aug	Frontier Airlines
28 Aug	Frontier Airlines
20 Aug	Frontier Airlines
21 Aug	Frontier Airlines
18 Aug	Frontier Airlines
30 Aug	United	direct
31 Aug	United	direct

Also check the deals for return flights from Portland to San Francisco in August.

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 one-way flights from Portland to San Francisco in August from 89€

One-Way flights