Train from Sicily to mainland italy

Have you tried Trenitalia, the website of the Italian railways? Both from Palermo and Catania I found several daily connections to Reggio di Calabria on an at random day next week. There are even two direct daytime Intercity services to Naples, if that part of Italy would be your destination.
There is no need of or advantage with advance buying tickets when you take Regionale trains. These come without reservation and have a fixed price. Advance-bought tickets for the Intercity service can come with a EUR 10 discount.

For trains, you should use Trenitalia: https://www.trenitalia.com/tcom-en. Note that even on this English language version of the website, you will need to use the Italian versions of the city names, such as Napoli, Roma, Firenze, Milano, and Venezia.

You may also want to look into flying, particularly if you're looking to go to Rome or further north (the train rides are VERY long, and some report that they are also uncomfortable). While Palermo is a larger city, Catania has the larger airport; both have lots of flights to mainland Italian cities. Rome has a ton of flights from Sicily, with a choice of airlines. Naples and Milan have the next most frequent flights, but even smaller airports like Venice or Turin will have 1-2 flights a day. To find flights, use Skyscanner: https://www.skyscanner.com/. However, be sure to go to the airline's website and do a "dummy booking" (up to the point where you put in your credit card) to learn about all fees and rules.

If you going from Palermo to Naples, there's an overnight ferry. I haven't taken it, but those who have give it good reviews (certainly better reviews than the train usually gets).

Finally, unless you want more spam than you are already getting, remove your e-mail from your message! To do this, make sure you are logged in on this website. On your first post, you can then edit it. If someone wants to contact you privately, they can send you a private message. You can set your profile here to give you an alert in your e-mail whenever someone sends you a private message, or when someone posts on this thread. to do this, make sure you are logged in, then click on your name, then click "Edit Profile."

I used Rome2Rio to find train tickets for our trip from Catania to Paestum. The ferry ride across the Messina Strait is beautiful!

Rome2Rio is an unnecessary detour. Since you want a train, go straight to the train site already indicated.

For what it's worth, I thought the experience of a train loading onto the ferry was pretty neat. But, depending on which cities you're traveling to/from, I agree that you may want to consider a flight.

I took the train from Rome to Cefalu Sicily 2 years ago and wouldn’t do it again- it took so long and was delayed coming back- I lost 2 days for travel. I would suggest flying unless you have a lot of time to spare. It was interesting watching the train get on the ferry, however!

I use this site for buying train tickets that I got on here from another forum member.
https://loco2.com/en?gclid=EAIaIQobChMI68W8x-qW3AIVULbACh2hVwdcEAAYASAAEgIeSvD_BwE&utm_content=Brand+Pure+-+Exact&utm_keyword=loco2+com

Its called Loco2- very user friendly, compares all train companies, very easy to use I highly recommend.

Happy Travels✨💫