The Danish manufacturer will install seven V90-3MW turbines at the project in the western province of Guanacaste.
Delivery of the turbines will start in the third quarter of 2014, and the wind farm is expected to be commissioned before the end of the year.
As well as installation, the contract includes a ten-year service agreement, featuring Vestas' remote surveillance system.
The order has been placed by Tilawind Corporation, a special-purpose company owned by Costa Rican corporation New Tessela together with developer Gruman Resources.
This is the first order for megawat-capacity Vestas turbines in Costa Rica, with the manufacturer previously having installed V52-850kW machines in the country.