There is a low fare American Airlines fare today for Portland PDX to Tokyo Haneda HND or Tokyo NRT at $503 to $512 round trip for departures dates September to November. This one may be gone soon since it was available from Seattle earlier and that fare is now in the $800s.
There appear to be about 25 dates in Sep-Nov with American Airlines tickets for PDX-HND or PDX-NRT $503 to $512 round trip fares.
The best deal I found is American Airlines PDX-NRT at $502.26 round trip as a one-stop via LAX.
American Airlines Portland PDX – Los Angeles LAX – Tokyo NRT – Los Angeles LAX – Portland PDX
$502.26 round trip Thu Sep 22 – Wed Sep 28
There are more AA tickets for this low fare deal flying Alaska Airlines flights PDX-LAX-SFO connecting to Japan Airlines outbound San Francisco to Tokyo Haneda. The inbound segments are Japan Airlines to SFO and a direct flight with Alaska Airlines SFO-PDX. All the $507 itineraries I checked followed this same routing.
American Airlines Portland PDX – Los Angeles LAX – San Francisco SFO – Tokyo Haneda HND – San Francisco SFO – Portland PDX
$507.36 round trip Mon Sep 12 – Thu Sep 22
Portland PDX – Los Angeles LAX – San Francisco SFO – Tokyo Haneda HND – San Francisco SFO – Portland PDX
$507.36 round trip Tue Nov 1 – Tue Nov 8
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