Meetings with The President of Ireland, Michael Higgins, and with The Taoiseach, Leo Varadkar, are both planned.
Fittingly, Meghan Markle arrived wearing a forest green pencil dress by Givenchy which featured pocket detailing, while holding a tan leather tote.
Their itinerary includes a variety of events and visits to various organizations "which are central to Irish life", according to Kensington Palace.
Harry gave his first address of their trip, which began on Tuesday evening as the newlyweds arrived in Dublin airport, at a garden party in the British Ambassador to Ireland's residence in Glencairn.
The Book of Kells is one of Ireland's greatest cultural treasures, and is on display at Trinity College in the heart of Dublin.
The head of the Royal Air Force, air chief marshal Sir Stephen Hillier, said that it is a "hugely important day" and the "pinnacle" of the centenary celebrations.
Meghan looked at ease with her first engagement with her husband - proving that her royal training schedule under the watchful eye of the Queen was paying off.
The American actress turned British royal, who was just yesterday criticized by social media fashionistas for wearing a "drab" olive green ensemble to Prince Louis' christening, set the world ablaze in a stunning custom Dior hours later when she joined fellow royals to celebrate Royal Air Force's 100th anniversary celebrations at Westminster Abbey this morning.