Trip Planning / Switzerland-Ireland-Scotland

We have been to all three several times. I suggest doing Switzerland last, since its mountain scenery is the most spectacular. (although Scotland is our favorite country.)

Of those three countries, Scotland was my hands down favorite.

We did a 2 week tour of Ireland last summer and have had a few days each in Switzerland and Scotland ( would like more). All were lovely and there are advantages to each. However a hard question to answer without knowing what kind of trip you plan (diy or join a group), what do you like to see (scenery, castles, museums, local culture, etc), finances (Switzerland is very expensive).

I have not been to Scotland (yet), but between Ireland and Switzerland, I highly preferred Switzerland. Also curious as to why you're adding Switzerland as it seems to be an outlier. I would do something more like Ireland, Scotland, and Iceland; or Ireland, Scotland, and Paris (assuming you've already done London; if not, get thee to London stat). Switzerland is easily combine-able with countries like France, Italy, Germany, etc. via train as opposed to having to fly.