According to Travels Abroad of the President, Office of the Historian, since 1928 only seven U.S. presidents have visited Costa Rica.
They are:
Herbert C. Hoover
Good will trip. [Visit made as President-elect.] November 28, 1928
John F. Kennedy
Attended Conference of Presidents of the Central American Republics. March 18–20, 1963
Lyndon B. Johnson
Informal visit; met with President Trejos. July 8, 1968
Ronald Reagan
Official working visit; met with President Monge and President Magana of El Salvador.December 3–4, 1982
George Bush Sr.
Attended Hemispheric Summit Meeting. October 27–28, 1989
Bill Clinton
Attended a Summit Meeting of Presidents of the Central American Republics. May 7–9, 1997
Barack Obama
Met with President Laura Chinchilla and leaders of the Central American Integration System. May 3–4, 2013
** In researching this article I found a discrepancy: the U.S. State government website says Reagan visited December 1983, however, an article in La Nacion has Reagan visiting Costa Rica in December 1983.