Hormuz and Bab el-Mandeb

Where each one is

The Strait of Hormuz sits at the mouth of the Persian Gulf, with Iran on the northern shore and the Omani exclave of Musandam on the southern. It is about 21 nautical miles across at its narrowest.

Bab el-Mandeb lies roughly 2,000 nautical miles to the south-west, between the Horn of Africa and the Arabian Peninsula — Djibouti and Eritrea on one side, Yemen on the other. It is the southern entrance to the Red Sea and measures about 16 nautical miles at its narrowest, with Perim Island splitting the passage into two channels.

They are in series, not parallel

This is the part that gets confused. The two are not alternative routes; for much of the traffic that uses them, they are consecutive gates on the same voyage.

A tanker loading in the Gulf and delivering to Europe passes Hormuz first, then Bab el-Mandeb, then the Suez Canal. Closing either one does not push traffic onto the other. Closing Hormuz stops the cargo leaving at all; closing Bab el-Mandeb sends it round the Cape of Good Hope instead, adding weeks.

Different kinds of vulnerability

Hormuz has no alternative. Pipelines that bypass it exist, but their combined capacity is a fraction of what moves by sea, and there is no second waterway out of the Gulf.

Bab el-Mandeb does have an alternative, and it is simply expensive: the route around southern Africa. That difference — no substitute versus a costly substitute — is why the two chokepoints behave so differently when either is disrupted.

Common questions

Which is narrower, Hormuz or Bab el-Mandeb?

Bab el-Mandeb, at about 16 nautical miles at its narrowest against roughly 21 for Hormuz. Usable lane width matters more than either figure.

Can ships avoid the Strait of Hormuz by using Bab el-Mandeb?

No. They are consecutive points on the same route out of the Gulf, not alternatives. There is no other sea exit from the Persian Gulf.