Human waves followed in a continuous or intermittent migration from the Arabian Peninsula through multiple entrances, where these migrations used these passages to reach the heart of Sudan.

The most prominent of these were Suez and the Sinai Peninsula, which were among the most important crossings from which Arab migrations departed from the northern part of the Arabian Peninsula, crossing into Egypt and then from there to Sudan and the rest of the African countries. The Isthmus of Suez remained the main route through which Arab tribes flowed towards the Nile Valley. However, the entry of Arabs into Sudan via Egypt before Islam did not result in deep-rooted effects, as their presence was most likely confined to the eastern part of the country, which is the western region of the Sinai Peninsula, where the Suez Canal had not yet been dug.

Hence, the Isthmus of Suez was the most important route taken by the migrating human groups, as mentioned in the Holy Quran and the Book of Genesis, where these human waves took it at close intervals.

The Red Sea also contributed as a passage for communication between the Arabian Peninsula, Sudan, and the Nile Valley, as crossing that sea from the eastern Red Sea ports faced no obstacles over the days.

The Bab al-Mandab also represented and continues to represent a current of human migration since ancient times, as the inhabitants of Southern Arabia spread along the eastern coasts of the African continent and then headed north and west, with Arab groups settling in Abyssinia and Sudan. Subsequently, some of them infiltrated into the Maghreb, and their civilizational and cultural impact appeared long before the birth of Christ, as they spread their Arab culture there. In fact, their oldest written Arab artifacts date back to the fourth century BC, while Arab migrations had infiltrated through the Bab al-Mandab since the seventh century BC.