The Constitution of Costa Rica establishes different ways of acquiring nationality. The grounds for acquisition are based on the principles of ius sanguinis, ius soli, and ius domicili. Article 14 of the Constitution - Individuals who are Costa Rican by naturalization include:

1. Those who have acquired this nationality under previous laws.
2. Nationals of other Central American countries, Spaniards, and Ibero-Americans by birth, who have officially resided in the country for a minimum of five years and who fulfill the other requirements set forth by the law.
3. Central Americans, Spaniards, and Ibero-Americans who are not so by birth, as well as other foreigners who have officially resided in the country for a minimum of seven years and who fulfill the other requirements set forth by the law.
4. Foreign women who, upon marrying a Costa Rican, lose their nationality.
5. Foreign women who, having been married to a Costa Rican for two years and having resided in the country during that same period, express their desire to acquire Costa Rican nationality.
6. Those who hold the honorary nationality granted by the Legislative Assembly. 

The prerequisites for individuals seeking naturalization includes demonstrating good behavior, proving a known occupation or means of livelihood, having proficiency in speaking, writing, and reading Spanish, undergoing a comprehensive assessment of the country's history and values, committing to regular residence in the national territory, and pledging allegiance to the constitutional order. 

Article 16 of the Constitution establishes that the Costa Rican nationality status is permanent and cannot be revoked.

Law of Options and Naturalizations, article 11 establishes that foreigners seeking naturalization must meet the following requirements and provide evidence of them to the Civil Registry:

1. Be of legal age and state their corresponding nationality.
2. Have a good conduct record and have been domiciled in Costa Rica for the time periods established in Article 14 of the Political Constitution, depending on each nationality group.
3. Have a profession or occupation, as well as known income sources such as rents, properties, or other earnings that provide sufficient means to meet their obligations and those of their family, if applicable.
4. Have not been convicted of intentional crimes during their stay in the country, nor be a repeat offender of negligent crimes, nor have been sentenced for repeated infractions.
5. Possess the ability to speak, write, and read the Spanish language, and further, have knowledge of the history of Costa Rica and its values. 

Additionally, the naturalization applicant must swear to respect the constitutional order and must also declare in writing their intention to continue residing regularly and permanently in the country.

Furthermore, they must also express in the same manner their renunciation of their original nationality, except in cases where the applicant is from a country with which Costa Rica has a dual nationality treaty.

Section 1 of the "Regulation on the procedures, requirements, and resolution criteria in matters of naturalization" provides specifically for the naturalization of individuals declared as stateless or stateless refugees. Stateless persons and stateless refugees must demonstrate having received the status of a stateless person or stateless refugee, having officially resided in Costa Rica for two years, possessing good conduct, and not having been convicted of specific crimes as defined by Article 15 of the Law of Options and Naturalizations. The Regulation does not cover refugees who have not been declared in a stateless situation.