Sometimes your physician can provide you with the recommended immunizations for Costa Rica travel. In some cases, you'll have to visit a travel clinic for the more obscure inoculations. You can search for a travel clinic through the CDC's Traveler Health webpage. Ideally, you should visit your doctor or travel clinic 4-6 weeks before departure to allow time for the vaccinations to take effect.
At present, the Center for Disease Control and Prevention recommends these Costa Rica immunizations:
Typhoid: Recommended for all Central America travelers.
Hepatitis A: "Recommended for all unvaccinated people traveling to or working in countries with an intermediate or high level of hepatitis A virus infection (see map) where exposure might occur through food or water. Cases of travel-related hepatitis A can also occur in travelers to developing countries with "standard" tourist itineraries, accommodations, and food consumption behaviors." The CDC.
Hepatitis B: "Recommended for all unvaccinated persons traveling to or working in countries with intermediate to high levels of endemic HBV transmission, especially those who might be exposed to blood or body fluids, have sexual contact with the local population, or be exposed through medical treatment (e.g., for an accident)." The CDC.
Routine Vaccines: Make sure your routine vaccinations, such as tetanus, MMR, polio and others are all up to date.
Rabies: Recommended only for travelers who will be in direct contact with animals.
The CDC also recommends Costa Rica travelers take precautions against malaria, such as antimalarial drugs, if they're traveling in Limon province.
Always check the CDC's Costa Rica Travel page to for up-to-date Costa Rica vaccination information and other travel health tips.