Cahir does Christmas the way an Irish market town does it: one big evening at the start of December when the lights go on, and the rest of it built around that. If you are going to make one trip, make it that one.
The lights switch-on
The Christmas lights are switched on in the town centre in early December. Santa does the switching, then arrives in the town afterwards. Locally this is the event of the season.
The tractor run
The thing that makes Cahir's switch-on different from every other town's is the Christmas tractor run. Tractors are decorated and lit and driven through the town in a parade, with prizes for the best lit, and the parade runs immediately before or alongside the lights going on.
It is genuinely worth seeing. A convoy of illuminated farm machinery moving through a medieval town is a specific and excellent kind of Irish, and it draws large crowds for a town this size.
Santa's grotto
The grotto is at the Cahir Tourist Office in the town centre, and it runs across the switch-on weekend. Santa arrives on the Saturday evening after the lights, and the grotto opens again on the Sunday afternoon.
Being in the tourist office rather than a shopping centre is the whole character of it: small, central and unhurried, with none of the queuing that grottos in bigger towns involve.
Dates change every year
The one thing this page cannot tell you is the date, because it moves with the calendar and is set locally each year. Check Cahir community channels, Tipperary County Council's community listings, or the local radio and papers in late November. They will have the date, the parade time and the grotto hours before anyone else does.
Shopping and eating
Shopping in Cahir covers the independents, which is where a Christmas present from Cahir will come from: the Craft Granary, the boutiques and The Black Bee. Cahir Farmers Market on a Saturday morning is the place for the food end of it.
For the evening, the pubs and the restaurants are busy in December and worth booking rather than chancing.
If you are visiting
Getting to Cahir covers arriving, and the accommodation pages cover staying: hotels, bed and breakfast and self catering. The town is compact enough that everything on this page is within a few minutes' walk once you have parked.
Note that Cahir Castle and the Swiss Cottage are Office of Public Works sites with seasonal arrangements over the winter, so check with them before building a December day around either.