Asiana has a low fare of $523 round trip for San Francisco to Manila, Philippines via Seoul Incheon ICN, South Korea.
Low fare departure dates are avaialble from September to mid-May 2020. There are even lower fares at $456 round trip on some dates with China Southern Airlines. Asiana looks like a better flight schedule.
Here is an itinerary during Thanskgiving week 2019.
Asiana Airlines San Francisco SFO – Incheon ICN – Manila MNL – ICN – SFO