The phrase “coastlines are 12 miles apart” usually refers to territorial seas or very narrow sea gaps between countries, but there is no single standard list of exact coastline pairs that are precisely 12 miles apart everywhere along them.

What “12 miles” usually means

Most modern references to “12 miles” and coasts come from maritime law, not from two landmasses being exactly 12 miles apart:

  • Under the UN Convention on the Law of the Sea, every country can claim a territorial sea up to 12 nautical miles from its coastline.
  • Where two countries lie close together, their 12‑mile claims may approach or meet, and boundaries are often drawn by agreement or by a median line.

So when people ask which coastlines are 12 miles apart, they often mean:

  • Places where opposite coasts are only a few to a few dozen miles apart , so the territorial seas nearly touch.
  • Or they are confusing “12 miles of coastline” (coast length) with “12 miles apart” (distance across water).

Example of “12‑mile” coastal context

A good illustration of “12 miles” related to coasts is Bosnia and Herzegovina:

  • Bosnia and Herzegovina has only about 12 miles of coastline on the Adriatic Sea near the town of Neum.
  • This is a length of coast belonging to one country, not a gap between two facing coastlines.

Other states also have very short total coastlines (like Monaco and Tuvalu), but again this is coastline length , not distance between coastlines.

Why there isn’t a neat list

Identifying coastlines that are exactly 12 miles apart along some line would require:

  • High‑resolution geographic data and
  • Precise measurement between every pair of facing shores worldwide.

Public articles and reference lists instead focus on:

  • Total coastline length per country.
  • Legal limits such as 12‑mile territorial seas , 24‑mile contiguous zones, and 200‑mile exclusive economic zones.

Because of that, there is no commonly cited, authoritative list that says “Coastline A and Coastline B are 12 miles apart” in the same simple way you might see lists of shortest straits.

If you meant something more specific

If by “which coastlines are 12 miles apart” you meant:

  • Two specific countries or cities you’ve seen mentioned in a news piece or forum thread.
  • A narrow strait or channel (like where ferries cross between two countries).

Then sharing that name (e.g., “between X and Y”) would allow a more concrete distance check with maps or nautical data. Meta description (SEO-style):
Looking into “which coastlines are 12 miles apart” usually leads to maritime law and short coastlines, like Bosnia and Herzegovina’s tiny 12‑mile Adriatic shore, rather than a fixed list of coast pairs, because distance between opposing coasts varies and is not cataloged the way coastline lengths and 12‑mile territorial seas are.

Information gathered from public forums or data available on the internet and portrayed here.