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

One-Way flights

30 Sep	United	direct
09 Sep	United	direct
10 Sep	United	direct
17 Sep	United	direct
24 Sep	United	direct
23 Sep	United	direct
13 Sep	United	direct
29 Sep	United	direct
20 Sep	United	direct
25 Sep	United	direct

Also check the deals for return flights from Portland to San Francisco 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 one-way flights from Portland to San Francisco in September from 41€

One-Way flights