Four days in Dublin is considered the "perfect" amount of time for a first-time visitor in 2026; it is certainly not too much. A four-day itinerary allows you to explore the compact city center thoroughly—visiting Trinity College, the Guinness Storehouse, and the historic Kilmainham Gaol—while still having time for the city's famous "leisurely" pub culture. Crucially, a fourth day provides the opportunity for a coastal day trip. Many travelers use their final day to take the DART train to the fishing village of Howth for a cliff walk or to Greystones for a seaside lunch. Without those four days, you might feel rushed between the heavy historical sites and the vibrant nightlife of Temple Bar and Camden Street. If you stay longer than four days, you might find the city itself starts to feel small, which is when most people begin to head west toward Galway or the Cliffs of Moher to see the more rugged side of Ireland.