People from certain countries have a particularly hard time entering Costa Rica because they need a special visa known as the Restricted Visa. This is obtained through approval by a commission.
According to the Directorate General for Migration and Foreigners, the Restricted Visa Commission is made up of representatives of the Ministry of Foreign Affairs, Labor, and Public Security. They meet once a week to study the applicants.
The visa is needed for citizens of Afghanistan, Bangladesh, North Korea, Cuba, Eritrea, Ethiopia, Haiti, Iran, Iraq, Jamaica, Burma, Palestine, Syria, Somalia, and Sri Lanka. The reasons for these countries being on the list include economic reasons, security reasons, and the termination of international agreements.
There is a way to bypass the need for approval by this commission. That is to obtain a visa from the U.S. or Canada that would be accepted by Costa Rican authorities. These include the multiple visa from Canada and the tourist, crew, or business visa from the U.S. It does not apply with transit visas.