Packing formal attire

Rent or buy when you are in Italy.

Google these words to find a formal attire rental store in Rome:

NOLEGGIO ABITI DA CERIMONIA ROMA

There are lots in Rome. Just be sure you are there long enough before the ceremony to have time to rent or shop.

The other option is just to check a bag. It really isn't that big of an issue. Have documents, meds, etc with you in a small carryon bag and then just check your formal clothing through. Now if you are going to be renting formal wear anyway, then renting in Rome makes a great deal of sense.

Renting is a great idea, but if you have something you already own that you wish to wear, you could ship it home--are you traveling before or after the event?
Or, you can store some luggage while you tour, if you are flying round trip.
Schlepping it with you in a carry-on though will likely result in a wrinkled mess.

If you can meet the size and weight limits for carry on I wouldn't worry about wrinkles and instead just count on having the formal clothes pressed upon arrival in Rome.

Yes but formal dresses will take up so much space there will be little room for regular clothing. We need to know if Cathy is amenable to renting.

We did as Trotter suggests.

On one of our trips we packed evening dress for an opera at La Scala. My husband carefully packed his good suit in a large flat “packing envelope’ and kept that at the bottom of his 22” roller bag. I packed my long dress in a similar envelope. When we got to Milan, the last stop of our trip, he took his suit to the dry-cleaner up the street to have it pressed, and picked it up 2 hours later. My dress needed only a light “steaming” so I hung it in the bathroom while we showered.

Now that I've gotten used to the ease of packing light, I will never go back. It's liberating and I no longer have to worry about meticulously repacking "nice clothes" every time we change lodging. I would do everything I could to avoid carrying bulky suit jackets and dresses. Shoes, you are probably stuck packing.

You say "formal" but what does that mean in your parlance. For me that's a Tux/Dinner Jacket and slacks, with black tie. I'm not sure that is typical for wedding guests. Also, if it's a destination wedding, the dress code can be a bit more relaxed typically. I'd hate to have you go the hassle and cost unnecessarily.

Some of your options depend upon whether the event is at the beginning, middle or end of the trip.

Renting seems a good-ish option. I think you'll be surprised how expensive it is.

It's not Vietnam, but possibly there's a way to expedite alterations and get a nice souvenir if you contact someone like this in advance, explaining your situation : https://www.bazookamenswear.com/collections/suits in advance.

Everyone, thank you for the advice. I really appreciate it.
Cathy

Please let us know what you decide and how it works out--it is very helpful for future readers and us as well!