Photo: Photograph by Mike Peel (www.mikepeel.net)., CC BY-SA 4.0 Free historic sites in Dublin
Photo: Photograph by Mike Peel (www.mikepeel.net)., CC BY-SA 4.0 
Photo: Stephen Bergin steve_, CC0 Trinity College
Free outside, paid inside
Photo: Filip Scridon, CC BY-SA 4.0 National Museum – Decorative Arts and History
Free, always
Photo: William Murphy, CC BY-SA 2.0 Merrion Square
Free, always
Photo: William Murphy, CC BY-SA 2.0 Temple Bar
Free, always
Photo: J.-H. Janßen, CC BY-SA 3.0 Dublin Castle grounds and Dubh Linn Garden
Free outside, paid inside
Photo: Andreas F. Borchert, CC BY-SA 4.0 Glasnevin Cemetery
Free, alwaysFamine Memorial
Free, always
Photo: Giuseppe Milo, CC BY 3.0 Samuel Beckett Bridge
Free, alwaysCustom House
Free outside, paid inside
Photo: Rodhullandemu, CC BY-SA 4.0 O’Connell Street and the Spire
Free, always
Photo: Diliff, CC BY-SA 3.0 St Patrick’s Cathedral
Free outside, paid inside
Photo: Ingo Mehling, CC BY-SA 4.0 Christ Church Cathedral
Free outside, paid inside
Photo: Colin, CC BY-SA 4.0