Rome to Venice via Trenitalia: Book now or at station?

If you want to save money, book them now. You will have more flexibility if you wait, but it sounds like you know the schedule you want anyway. Note that when searching, look under the full Italian names of the stations - Roma Termini and Venezia Santa Lucia (S. Lucia).

It looks like the earliest you will be able to leave is 0650 from Rome, arriving at 1035 in Venice. There are 2nd class Super Economy rate tickets available for 39€ (instead of the full 80€). The latest you can leave is 7:25pm, getting back to Rome at 11:10pm. You could leave at 5:25 or 6:25 if you want to get back around 9 or 10pm as you mention (these are available for 29€ each instead of 80 right now).

Since the trip to Venice is 3h45 minutes each way, you'll be spending nearly 8 hours on the train and less time than that in Venice (5 hours in Venice if you want to be back around 9pm). I would think about spending at least one night there, but that is your choice of course. Many say that wandering Venice at night when it is less crowded adds to the magic of the location.

I agree with Devon. Venice is not well suited for a day trip. Unless the idea is just to check it off the list. At that time year it will be very hot, humid, and crowded so plan accordingly for long lines and some delays. I would book the tickets now to take advantage of the discount since you are locked into a schedule if doing in one day. It will be exhausting.

I agree - I'd rather stay overnight in Venice, but if you are going to commit to this travel plan, you might as well lock in the train tickets at a better price, this route available starting four months out from Trenitalia.

I also agree with the others. Venice is not the most ideal for a day trip from Rome, due to the travel times (3H:45M each way) to get there and back. However, it's certainly possible.

As the others have said, you can get substantial discounts with Super Economy fares by pre-purchasing tickets as early as possible. I normally use second class tickets, as (IMO) there's no reason to pay more for first class. Your tickets will specify which Car No. (Carrozza) and Seat No. (Posti) you'll be sitting in.

One important point to note is that the tickets for premium trains such as the Freccia high speed versions, are specific to train, date and departure time so you MUST only use the train specified on your ticket (ie: Freccia Argento 9402). If you board any other train, you'll be subject to hefty fines, which will be collected on the spot! Also, If you'll be travelling on any Regionale trains (such as the Leonardo Express from the airport) or Buses during your visit, you MUST validate your tickets prior to boarding on the day of travel or again, hefty fines.

You could also travel from Rome to Venice using the relatively new Italo high speed trains, although they depart from Roma Tiburtina rather than Termini (both services use the same station in Venice). Check their website for schedule and pricing information.

If you decide to purchase tickets from Trenitalia for that trip, you may find it helpful to have a look at the excellent Ron In Rome website (scroll down to the part for purchasing tickets online).

Like making a day trip to Las Vegas from Los Angeles. You can say you've been there, but you really just had lunch.

Thanks for your replies and advice! :)