There's a reason Costa Rica (or the rich coast in English) is known as such. It's a place that's easy to fall in love with if you're someone who enjoys life from a hammock on the beach, zipping along on a surfboard, or even flying through a canopy of trees by zip line. Put lightly... you'll find a ton of amazing things that this country has to offer!
One of the most beneficial things Costa Rica has to offer is that it's also a great place to continue your education. Costa Ricans (or Ticos and Ticas) are very friendly and helpful and love to converse and chat up a storm. You should try to capitalize on this and speak to as many locals as you can when you visit. After all, one of the most fastest methods to learn a new language is to fully immerse yourself in it!
Costa Rica has the highest density of biodiversity of any country on Earth. It is stunningly beautiful, and offers many inspiring environments from Beaches to mountains to rain forests to volcanoes. Oftentimes, the schools where you study will be in very picturesque locales with three-toed sloths and howler monkeys sitting in on your lessons from the trees outside your classroom.
Costa Rica has a literacy rate of 95% which means that it is one of the most literate countries in the world. The demand for higher education has helped to increase the amount of high quality schools and universities, as well as many great study abroad programs across the country. You should have no problem finding a program that fits your needs with courses from spanish language to marine biology and everything else in-between available to students to choose from.
One phrase you will be sure to hear more than any other on your trip will be "Pura Vida." It is a very common saying Costa Ricans will use that means "pure life" and truly explains how many locals live their lives. Ticos are very welcoming and friendly and will try to help you out even if they don't know the answer to your question.
There is such a thing as Tico Time that you will need to get used to... It is common for them to show up 15-20 minutes late, and it is actually expected! Don't worry if you think you'll be late for your class, because odds are, the teacher won't start until a quarter after your scheduled time!
Take a look at a few Spanish Immersion programs and see if Costa Rica is the right choice for you. You should have no shortage of choices, but don't be afraid to contact them with any questions you might have. I'm sure they will be very helpful. Don't forget to tell them "Pura Vida!"