Trump is set to land at Shannon Airport in County Clare, where he'll be met by Taoiseach (prime minister) Leo Varadkar.
Local anti-Trump protesters are well-prepared for the grand arrival and have been constructing a "peace camp" at the airport.
Campaign group Shannonwatch announced that a major protest would take place outside the airport at 18:00. Taking part in the protest are local environmental, pro-Palestine, and anti-war groups.
The protesters are going to deliver letters to Trump and Varadkar, calling for an end to the US military use of Shannon Airport as a refuelling stop and the "environmental destruction of the planet".
Local police are said to be going to roll out the biggest security operation in Clare since the 2004 visit of George W. Bush.
Trump is set to fly by helicopter to his golf resort in Doonbeg, where he will stay overnight. He is unlikely to face public discontent in the small town, where his presence is boosting the local economy.
But the Stop Trump Ireland coalition plans to stage a big protest in Ireland's capital, Dublin, on Thursday at the Garden of Remembrance at 18:00, local time. A six-metre-tall "baby blimp" is also set to fly over Dublin after Tuesday's appearance in London.
Additional protests are scheduled to take place in Galway, Cork, Sligo, and other locations across the country.
The coalition, which comprises over 50 human rights and anti-racism organisations, was going to stage a similar rally in July 2018 during Trump's visit to the UK, but it was cancelled after he opted not to visit Ireland.