All three major U.S. airlines American, Delta and United have San Francisco to Liberia, Costa Rica on sale for $300 to $330 for dates from May 2016 through March 2017. Not all dates are available with all airlines, but there are several dates in every month between these three airlines. Peak season for Costa Rica is late November to early April.
Delta and United had this route on sale last week and now American Airlines joins the sale.
American Airlines service tends to have at least one overnight stopover or a couple of connections, not probably best for those who really want miles on AA or an overnight in Miami, rather than most convenient schedule for Costa Rica.
American Airlines San Francisco SFO – Miami MIA – Liberia, Costa Rica LIR
$316.08 round trip Saturday July 9 – Friday July 15, 2016
This itinerary has overnight in Miami in both directions.