The modern coasts of the peninsula are, on the west the Red Sea and the Gulf of Aqaba, on the southeast the Arabian Sea (part of the Indian Ocean), and on the northeast, the Gulf of Oman, the Strait of Hormuz, and the Persian Gulf. Its northern limit is defined by the Iranian and Iraqi mountain range of the Zagros collision zone, a mountainous uplift where a continental collision between the Arabian Plate and Asia is occurring. It merges with the Syrian Desert with no clear line of demarcation.

In the ancient and medieval eras, Roman and Arab geographers viewed all of the lands located on the Arabian Plate as one geographical unit. The Arabian plate extends from the Red Sea to the Zagros mountains and from the Gulf of Aden along the Mediterranean Sea coast to the northwestern limit defined by the Taurus Mountains of southern Turkey. During this period, Eilat Israel, Aqaba Jordan, and Taba, Egypt were located in Arabia Petraea.

Geographically, the Arabian Peninsula includes the western regions of Iraq and parts of Syria. Politically, however, the peninsula is separated from the rest of Asia by the Euphrates river.

The following countries either are, or have been, considered part of the peninsula:

• Bahrain, an island nation off the east coast of the peninsula.
• Iraq
• Kuwait
• Oman
• Palestinian Territories
• Israel
• Qatar
• Saudi Arabia
• Syria
• Jordan
• United Arab Emirates
• Yemen, the sole republic on the peninsula.

With the exception of some regions in northern Syria and northern Iraq, the countries mentioned above are geographically and historically part of the peninsula. However, only six countries of the above list are politically considered part of the peninsula. They form the Gulf Cooperation Council (GCC), mainly known as the Arab gulf states.

As of 2008, the estimated population of the Arabian Peninsula is 77,983,936.

Ancient history

In his book, 'The Real Eve', Oppenheimer claims based on mitochondrial evidence in conjunction with the contemporary environment (ie glaciation, sea levels) corresponding to these molecular clock timelines that the very first humans to leave Africa crossed the virtually dry mouth of the Red Sea onto the Arabian peninsula. They travelled along the coastline of the peninsula before crossing into Southern Asia.