Colombia usually classifies its geography into five natural regions, the Andes mountain range, a region shared with Ecuador, and Venezuela; the Pacific Ocean coastal region shared with Panama and Ecuador; the Caribbean Sea coastal region, shared with Venezuela and Panama; the Llanos (plains), shared with Venezuela; to the Amazon Rainforest region shared with Venezuela, Brazil, Peru, and Ecuador. Colombia is the only South American country that has a coastline on both the Atlantic and Pacific oceans since it borders one of its main marginal seas, the Caribbean Sea.

Source: Wikipedia