Most travellers arrive at Khartoum International Airport, which sits surprisingly close to the city centre — a 15-minute taxi ride from the downtown hotels and embassies. The airport handles direct flights to several European, Gulf, and African capitals; intercontinental connections almost always route through Dubai, Doha, Cairo, or Istanbul. Visas must usually be arranged in advance through a Sudanese embassy.
Overland entry is possible from Egypt (the long Lake Nasser crossing to Wadi Halfa and then south by train or bus), from Ethiopia at Metema, and historically from South Sudan and Chad, though border situations change with the security picture. Bus connections from the Egyptian and Ethiopian borders run direct to Khartoum's main bus terminal next to Souq Al Arabi.
Note that the security situation in Sudan has been highly volatile in recent years. Check current travel advisories before planning a visit; some periods the airport has been closed and overland routes restricted.