Which of the following countries does NOT share a land border with Saudi Arabia, being connected to it only by a causeway over water?

The correct answer is Bahrain, an island nation that does not share any land border with Saudi Arabia. Instead, the two countries are connected by the King Fahd Causeway, a roughly 25-kilometre bridge-and-causeway system built over the shallow waters of the Gulf, opened in 1986, linking the Saudi city of Khobar to Bahrain's Manama area. Jordan is incorrect because Saudi Arabia and Jordan share a recognised land boundary along the kingdom's northwestern frontier, running through desert terrain near the Wadi Araba region. Iraq is incorrect because Saudi Arabia borders Iraq along its northern frontier, a boundary formalised in agreements during the twentieth century and still in effect. Yemen is incorrect because Saudi Arabia shares its longest land border with Yemen along the southern frontier, a boundary that has been the subject of historical disputes but remains a genuine land connection nonetheless. Altogether, Saudi Arabia's seven land-border neighbours are Jordan, Iraq, Kuwait, Qatar, the UAE, Oman and Yemen, while Bahrain remains the sole nearby Gulf state reachable only by sea-crossing infrastructure. The common exam confusion here arises because Bahrain is geographically so close to Saudi Arabia's Eastern Province, and the causeway is so heavily travelled, that many candidates mistakenly assume a land border exists. The revision takeaway is to remember Bahrain distinctly as an island state connected by causeway, not by land, when listing Saudi Arabia's neighbours.