Puerto Limón, commonly known as Limón (Spanish for "lemon"), is the capital city and main hub of Limón province, as well as of the cantón (county) of Limón in Costa Rica. It has a population of about 60,000 (including surrounding towns), and is home to a thriving Afro-Caribbean community. Part of the community traces its roots to Jamaican laborers who worked on a late nineteenth-century railroad project that connected San José to Puerto Limón. Other parts of the population trace their roots to the Nicaraguan, Panamanian, and Colombian turtle-hunters who eventually settled along the Province of Limón's coast. Until 1948, the Costa Rican government did not recognize Afro-Caribbean as citizens and restricted their movement outside Limón province. As a result of this "travel ban", this Afro-Caribbean population became firmly established in the region, which influenced the decision to not move even after it was legally permitted. The Afro-Caribbean community speaks Spanish and Mekatelyu, a creole of English.

Puerto Limón contains two port terminals, Limón and Moín, which permit the shipment of Costa Rican exports (primarily banana) as well as the anchoring of cruise ships. A small island, Uvita Island, is just offshore.
Puerto Limón is famous in Costa Rica for its yearly fall festival called carnaval which occurs the week of October 12, the date Columbus first anchored off Limón's coast in 1502, on his fourth voyage. The event was started by local community leader and activist, Alfred Josiah Henry Smith (known as "Mister King"), who helped organize the first carnaval in October 1949. The event stretches about a week (across two weekends), and includes a parade, food, music, dancing, and, on the last night, a concert in the Parque Vargas headlined by a major Latino or Caribbean music act. Previous artists have included Eddy Herrera (2002), Damian Marley (2003), El Gran Combo de Puerto Rico (2005), and T.O.K. (2006).

Although the show goes on rain or shine, the event has recently suffered some setbacks. Organizers cancelled carnaval in 2007 due to a major dengue outbreak, and again in 2008 due to major municipal trash-removal issues and related health worries. While trash removal had long been an issue due to lack of trucks and a 62-mile haul to the nearest landfill (in Pococí), the ordered closure of this and other landfills in 2007 meant Puerto Limón had to send trash 135 miles to Alajuela and pay a higher disposal fee. The situation led to a bottle-neck in trash removal, which, combined with the major dengue breakout, caused organizers to cancel 2008's carnaval as a precautionary measure. Given the severity of the situation, the city bought land in nearby Santa Rosa and, in April 2009, opened its own landfill (called El Tomatal). Given the improved situation, carnaval picked up in 2009 after its two-year hiatus.