gunanacste is the most northern province of costa rica. lake arenal and bahia salinas are the only two spots for wind- and kitesurfing. both locations have a school and accomodations nearby.
liberia is the main town of guanacaste and has its own international airport (LIR) served by all major us airlines (from san jose airport (SJO) it takes 3 hours by bus or car to liberia. there are at least ten buses a day from 5 usd a person)
bahia salinas (salinas bay) is 30 min. north of liberia next to la cruz. bus (from 1 usd) and cab (from 50 usd) services are available, pick ups can be organized.