Travel Adapter

It makes a difference knowing what you intend to plug in.

Iphone charger and Kindle charger, mostly. Not planning to take a hair dryer, etc.

That would be an adapter-just a little plug-like thing, but I know England and France use different styles of outlets. I'm guessing Ireland's plugs look like England's, but I haven't checked. If I'm right, you'll need either two styles of adapter or a universal one that covers all bases. You can find adapters on Amazon. I'm nearly certain I've seen the continental version needed for France at my local Container Store, but I don't know that they have the English style. Both types are usually in stock on this website, too, but I haven't looked into the provisions for rush shipping. I'd expect at least the Euro version to be sold somewhere in the airport from which you're departing on your internationaal flight, but that msy be the most expensive option..

Three questions that answer all such problems:
Q1) Will your appliances accept 220V 50Hz, or are they only 110V 60Hz (read the info plate)?
ANSWER) Iphone charger and Kindle charger should accept both types of electricity. No transformers (converters) needed, just adapters

2) Are they 2-pin or 3-pin (2 with earth)
ANSWER) Iphone charger and Kindle charger are two pin.

3) Which countries are you going to - France and Ireland.

Therefore you need a 2-pin adapter for France. If you have US plugs, it looks like this: https://cdn.a4c.com/media/catalog/product/cache/1/image/520x520/9df78eab33525d08d6e5fb8d27136e95/s/a/samsung-us-to-euro-plug-adapter-5-pack-alt.jpg
Note the triangular ends. If it has round ends it may not fit in all sockets.

Ireland uses UK plugs. You want something that looks like this: https://images-eu.ssl-images-amazon.com/images/I/41Xm1fI%2BKsL.jpg
Note there is no 2-pin option for UK/Irish plugs, it has to be 3-pin.

The adapter plugs sold right here in the RS store work perfectly in France and Ireland for low wattage devices like cell phones and tablets as long as those are dual voltage capable. You will need one European and one UK to cover your destinations. And they only cost $1.

We are going on Best of Switzerland tour. Can I use the same adapter for the entire tour or are parts of Switzerland different? Also which one do I need?
Thanks,
Sue

Can I use the same adapter for the entire tour or are parts of Switzerland different?

I would expect that all of Switzerland would have the same standard electric plug/socket. It's Switzerland.

Swiss standard plugs are similar, but not the same as the German Schuko type plug starting with the ground pin. However, if you are only needing an un-grounded plug (two pins) the plug adapter that Rick Steves sells is close enough to fit the Swiss outlets. Both the Schuko and Swiss plugs have pins 19 mm apart but the Schuko pin is slightly larger in diameter than the Swiss plug. Our RS adapter was a snug fit in the Swiss outlets but did fit with a little pushing and came out with a little pulling.

If your Schuko plug doesn't work hotels have loaner plug adapters to match Schuko grounded plugs to the three-electrode Swiss outlets.

Sue, To expand on what Edgar said.
For two pin plugs, Switzerland is the same as Germany, France etc. For a US plug you need the adaptor I posted last time: https://cdn.a4c.com/media/catalog/product/cache/1/image/520x520/9df78eab33525d08d6e5fb8d27136e95/s/a/samsung-us-to-euro-plug-adapter-5-pack-alt.jpg
Make sure it has the triangular ends. Modern sockets are recessed, and larger non-standard plugs on some adapters don't fit.

Three pins are different. The Swiss have the 3rd earth pin in a triangular form. Photo: http://www.worldstandards.eu/WordPress/wp-content/uploads/electricity-tiles-type-J-200-px.jpg
You don't need a three pin adapter, but if you did you would need a different one for Switzerland.
You can sometimes force a Schuko plug into a non-recessed Swiss socket (as Edgar did), but it is not recommended. You may break the socket, and you will not have an earth connection.