The Caribbean Sea is a distinct marginal sea of the Atlantic Ocean, not part of the Pacific. It's situated in the Western Hemisphere, bounded by:
It connects to the Atlantic through multiple passages between the Antilles islands and to the Gulf of Mexico via the Yucatán Channel. While hydrologically part of the Atlantic system, it's a semi-enclosed basin with distinct circulation, ecology, and climatic characteristics.
The confusion sometimes arises because the Caribbean is "in" the broader Atlantic realm, but it's a named sea with its own identity—similar to how the Mediterranean is part of the Atlantic system but distinct from it.