Which is the happiest nation in the world? There are many nations but the one which is said to be the happiest according to the survey is Costa Rica. Costa Rica is rugged, the rainforested country with coastlines on the Caribbean and Pacific. Although its capital, San Jose, is home to cultural establishments just like the pre-Columbian Gold depository, Costa Rica is thought for its beaches, volcanoes and large variety. Roughly 1 / 4 of its space is formed from protected jungle, wealthy with life as well as spider monkeys and quetzal birds.