Well, it's none of the above! The largest city in Costa Rica is actually San José. So, while Puerto Rico and San Salvador are off exploring, and San Juan is busy being the capital of Puerto Rico, San José is happily holding the title of the largest city in Costa Rica.
The largest city in Costa Rica is San José. To determine this, you can either have prior knowledge or use research methods. One way to find the answer is by conducting an internet search. Simply enter "largest city in Costa Rica" into a search engine, and it should provide you with the information that San José is the largest city in the country.
