"The transaction will be executed, with God's help, on the scheduled dates today and tomorrow," Abdel Kader Mortaza, the Yemeni official in charge of prisoner affairs, said in a tweet.
"The preparations have been completed by all parties," he added.
The two sides resolved to swap some 15,000 detainees as part of a peace deal brokered by the UN in Stockholm back in 2018.
They have since undertaken sporadic prisoner exchanges, but this week's planned swap would mark the first large-scale handover since the coalition began its aggression on Yemen in 2015.
UN envoy Martin Griffiths hailed it as a "very important milestone" when the agreement was struck after a week of talks in Switzerland last month.
A spokeswoman for the International Committee of the Red Cross, which is handling the logistics of the operation, said their teams were present at a number of different airports involved in the transfer.
"The preparations are ongoing, if everything goes as planned, we hopefully expect the release operation to take place in the coming few hours," she told AFP Thursday morning.
Al-Masirah television said the first group of Yemeni prisoners was expected to arrive Thursday at the international airport in the capital Sana’a.
The planned prisoner exchange comes after the release Wednesday of two Americans held captive in Yemen, in an apparent swap for some 240 Houthi Ansarullah supporters who were allowed to return home after being stranded in Oman.
The movement also sent back the remains of a third American who died in captivity.
Since March 2015, Saudi Arabia has been conducting a bloody military aggression in Yemen with help from its regional allies, and using arms supplied by its Western backers. The aim of the war has been to bring Yemen's former president Abd Rabbuh Mansour Hadi back to power and defeat the Houthi Ansarullah movement.
Since 2015, over 100,000 people have been killed, according to the US-based Armed Conflict Location and Event Data Project (ACLED).
