Delta and United Airlines have a fare from San Francisco SFO to Liberia LIR Costa Rica for around $300 round trip. There are low fares on one airline or the other and many dates both airlines from May into March 2017, including peak season January dates. Liberia LIR is the main airport in Costa Rica for Pacific Coast resorts in the major hotel chains along the Guanacaste region.
Delta Airlines outbound San Francisco SFO – Los Angeles LAX – Liberia LIR Costa Rica Wednesday June 1, 2016
United Airlines inbound Liberia LIR – Houston IAH – San Francisco SFO Wednesday June 8, 2016
Purchase as two separate one way tickets with Delta and United for lowest fare.
United Airlines San Francisco SFO – Houston IAH – Liberia LIR
$299.58 Saturday January 7 – Saturday January 14, 2017