Mongolia Region: East Asia Pre-pandemic visa rules Requirements Passport Validity 6 months Transit - Holders of confirmed onward tickets are permitted transit without visa in international transit area for up to 24 hours. Dual Nationality U.S. policy on dual nationality can be found here. Additional Notes Any foreign national staying in Mongolia more than 30 days is required to be registered at the Immigration Authority of Mongolia within 7 days. Sources: Embassy of Mongolia to the USA Timaticweb