County Kerry on Wikipedia.

Ardfert, the ruins of St. Brendan's Cathedral. © Christopher Skottowe (1965). Link1. Link2.

Ballybunion, Catholic Church. From an old postcard in Reg Dosell's Collection.
Ballydonoghue, St. Teresa. Previously in the "Unknown" section. Cathy Umbers, on behalf of a friend, was hoping to get an identification for a church in County Kerry, probably near Lixnaw (though it definitely isn't Luxnaw church itself). Although they obtained the identification though other sources, I'm glad to be able to include the solution here.
Ballyferriter, Gallarus Oratory. It's true purpose and date have been subject to much speculation. Link. The ruins of  Kilmalkedar Church. Link. Both © Christopher Skottowe (1965).

Cahersiveen, the O'Connell Memorial Church (interior view). From an old postcard in Reg Dosell's Collection. Now known as the Daniel O'Connell Memorial Church of the Holy Cross (R.C.), it stands on Main Street. Wikipedia dates it to 1888-92. 2026 Streetview. Link. The former St. Finnian (CoI) (2019 Streetview) on West Main Street, now in secular use. It's dated here to 1863-4. An old building on Old Market Street is known as the Penal Church (2009 Streetview). Read about its story here. Just a short walk north on the same street are the remains of Old Abbey of the Holy Cross - 2009 Streetview. Link.

Kenmare, Holy Cross (R.C., 1864). From an old postcard in Reg Dosell's Collection. A modern view, © Dennis Harper (2006). Link. Church at Bunane. Interior view. Both © Dennis Harper (2006).
Killarney.
Killorglin, St. James (R.C.). Interior view. Both from old postcards in Reg Dosell's Collection.

Listowel, St. John (CoI) on The Square. From an old postcard in Reg Dosell's Collection. It's now in use as a theatre (link). Just a stone's throw away is St. Mary (R.C.), © John Balaam (2022). Link. The history page dates it to 1829.

Muckross, Muckross Abbey. From an old postcard in Steve Bulman's Collection. An "interior" view, © Christopher Skottowe (1965). Link. Holy Spirit. An Irish church, photographed during a 1970 family holiday, from Chris Scales' collection. Previously in the Unknown section, it was identified by Tony Preston.        

Tralee, Dominican Church of the Holy Cross. © John Balaam (2008). St. John (R.C.). © John Balaam (2008).