trains in Italy

Not necessarily

You can take a fast train to Bologna( (which you can book ahead if you are sure of your dates)
Then regional to Ravenna ( departures about every hour)

Or regional to Ferrara change there to Ravenna (fewer departures)
No need to book in advance

See what Trenitalia suggests

You can also look up the route for tomorrow and then a month out to see the difference in price if you purchase tickets ahead of time.

www.trenitalia.com

Venice is Venezia

Your best option for getting between Venice (Venezia Santa Lucia station) and Ravenna is regional trains anyway - and regional trains are the same price in advance as they are buying them 15 minutes before you get on. There are no reservations on regional trains, so they can't sell out (sometimes you have to stand if a train is crowded.) You can even buy them on your phone using an app like Trenit. Or buy paper tickets from a machine at the stations, but don't forget to VALIDATE regional train tickets bought that way! (Validate in the yellow boxes at the station.) Otherwise you risk a big fine if caught with an unvalidated ticket.

Best option is to change in Ferrara, so you need at least one change of trains; there is no direct train between them.

On the other hand, you could decide to take an high speed train between Venice and Bologna to save 30 minutes. Note that a seat reservation is mandatory on high speed trains. It comes with the ticket and the cost is always included.

You can purchase all train tickets up to 15 minute before the scheduled departure time.

Buying on the day of travel, on high speed trains you'll pay the top, walk-up fare. It's called BASE on trenitalia.com and it's always displayed in advance together with the discounted fares (Economy and SuperEconomy).

Once a BASE fare has been published on trenitalia.com , it won't change. Unlike airlines, train fares are capped.

Unfortunately. Once all discounted tickets are sold out they are gone.

I don't see any Bologan connections that save time over changing trains in Ferrara. The fastest routings seem to involve a fast train to Ravenna and a regional from that point.

Thank you!