What vaccines or health precautions do I need?
A visit to your doctor about a month before you travel, the CDC's current advice for Costa Rica, and what to take to that appointment.
Book a visit with your doctor about a month before your trip. That gives time for any vaccine or medicine to take effect.
The CDC currently lists a hepatitis A outbreak in Costa Rica, so ask your doctor about that vaccine in particular.
The CDC keeps an up-to-date page for travelers to Costa Rica, with the vaccines it recommends and its advice on malaria prevention for some areas of the country. Take your itinerary along to the appointment, because the right advice depends on where you are going and what you will be doing: https://wwwnc.cdc.gov/travel/destinations/traveler/none/costa-rica
For mosquitoes and the sun, see Do I need to worry about mosquitoes or the sun?
We are travel specialists, not doctors, so we leave this one to your doctor and the CDC. If you need the regions on your itinerary for that conversation, just ask us.