He was received at an airbase by Saudi Defence Minister Prince Mohammed bin Salman, who is overseeing the military operation by nearly a dozen countries against the Huthi Shiites.
Hadi's whereabouts had been unknown since the Huthi rebels and their allies closed in on his refuge in the main southern city of Aden this week.
Yemen's acting foreign minister, Riyad Yassin, told reporters in Cairo that Hadi would take part in a two-day Arab summit starting Saturday in Egypt.