Ms Tsukamoto Michiko was 10 years old at the time of the bombing, and Ms Sora Tamiko was 3 years old. Both were affected by radiation exposure in the aftermath of the bombing.
A number of events have been organised in the course of the day, including meeting officials at the Department of Foreign Affairs to discuss Ireland's role in the Treaty on the Prohibition of Nuclear Weapons, and a reception hosted by the Lord Mayor.
They will hold a joint press/political briefing at 16:30 in Buswell's Hotel, followed by a conversation on their experiences and hopes for a nuclear-weapons-free world with local peace campaigners.
Peace Boat left the Japanese port of Yokohama on September 1st on its current Global Voyage for Peace, and will return there on December 17th, after visiting 24 ports across Asia, the Mediterranean region, western Europe and North and South America.