Most visitors to Costa Rica from the UK come through the States, as there are no direct flights from the UK. Total flying time is about 13-14 hours, depending on the route. If you come through the States you need an electronic transit authorization called an E.S.T.A which you can apply for on-line at the esta website.
The major US airlines that serve Costa Rica and have flights from the UK are American Airlines, United (formerly Continental), Delta and US Airways. We have found the cheapest and most frequent flights to be on United, transiting through Newark or Houston. You need to allow at least two hours transit time, whichever US airport you go to, and even longer at busy airports like Miami.
Costa Rica has two international airports San José (SJO) and Liberia (LIR); most of the US carriers serve both airports although Liberia has fewer flights and connections. Liberia is in the North West of the country, about four hours drive from San José and is located closer the Pacific beach destinations of Guanacaste. It is possible to come in one airport and exit through the other, if you don’t want to retrace your steps.
If you don’t want to transit through the States other options include going through Canada on Air Canada or Spain on Iberia.
The hubs for these airlines are:
American Airlines: Miami and Dallas
United: Newark and Houston
Air Canada: Toronto