Hi! Trains are leaving from the station every hour at .25
It takes about 2 hours to get to Venice.

Have fun!

The fast train takes 2 hrs or so and is part of the Eurostar Italia fleet (Venezia Santa Lucia - Firenze Santa Maria Novella). If you buy your tickets now, in advance you can get a "mini-fare" for around €20... on the day it will be more, around €40-50. There are also slower InterCity trains that take 3hrs and are a little cheaper (Venezia Santa lucia - Firenze Rifredi)

Check the Trenitalia website to get an idea of prices!

Regional trains are the slow trains and would take much longer. You want the fast AV trains.

http://www.trenitalia.com/cms/v/index.jsp?vgnextoid=ad1ce14114bc9110VgnVCM10000080a3e90aRCRD

If the kids are under 12 you can get a family discount.

http://www.trenitalia.com/cms/v/index.jsp?vgnextoid=91fb335a9a605210VgnVCM1000003f16f90aRCRD

Iyou want to take only Regionale trains, your route will be Firenze S.M.N.-Prato-Bologna-Venezia Santa Lucia. The fare is €2.30 for the first leg, €7.05 for the second leg, and €10.75 for the third leg.

We want to go on 8th may from Florence to Venice
When we checked on trenitalia, the option was E101 for 2 adults and 2 kids(4 & 9 yes old)
Pl advise how can I get cheaper ticket. Preferably I should reach by afternoon

The fare you quoted is for a direct high-speed EuroStar Italia train.

To get the fares I quoted, go to the Firenze S.M.N. station and buy Regionale train tickets for Firenze S.M.N.-Prato Centrale, Prato Centrale-Bologna Centrale, and Bologna Centrale-Venezia Santa Lucia. No reservations are possible on Regionale trains. Your tickets will be good on all Regionale trains on that route. Be sure to validate your tickets in the yellow boxes at the stations or you will be fined on the spot.

You can leave Florence at 07:10 and arrive in Venice at 11:03. Or leave at 09:47 and arrive at 14:03. Or leave at 10:48 and arrive at 15:03. Or leave at 12:47 and arrive at 17:03.

Unless budget is really a factor, I would not make multiple train changes with children and luggage.

the regionale trains at €21 odd [adding all those fares that Tim quotes together] are vey little cheaper than the fare the OP has been quoted, when the time factor is taken into account. I too would not like to be herding kids of that age round 2 changes of trains.

it seems to be a bit of a false economy.

Thanks a lot for this advise. Should I buy now or should I buy once in Florence. Is E29 (the current ticket charge) the highest or this can go even higher as we go closer to the date.

You should not buy tickets for the slow R trains in advance online as there are no discounts or reserved seats. There are more restrictions on R tickets purchased online than bought at the station. If you are going to buy the fast AV trains, the Mini Fares are advance purchase only.

If you decide to take a fast train, book now. If you wait until you get to Florence, the Mini fares will be gone. I think you can get family fare tickets anytime, but I don't know for sure.