Where does international airspace begin?

International airspace begins at a distance of 12 nautical miles (NM) off a nation's coastline. This boundary is established based on the United Nations Convention on the Law of the Sea, which recognizes that a coastal state has territorial rights over the airspace above its territorial waters, extending from the baseline, typically the low-water mark along the coast, out to 12 NM.

Understanding this boundary is crucial for navigation and flight planning, as airspace beyond this limit is generally considered international airspace, meaning aircraft are not subject to the laws of the coastal nation and can be freely traversed by international flights. This delineation ensures both security and freedom of navigation in the skies, allowing for regulated air traffic while respecting the sovereignty of coastal states up to the defined limit.

The other responses indicate different nautical mile distances that do not align with the established guidelines of airspace sovereignty. The 6 NM boundary is notably incorrect as it reflects an older standard that has been largely replaced. The options indicating 24 NM and 50 NM extend well beyond the recognized limits of territorial airspace without being supported by international treaty or customary law.