We are planning Rome and Venice in April. We are flying into Rome and out of Venice. Our return flight is at 6:30 am, which would be the best location to stay. If we stay in San Marco area will we have transportation early in the morning ? If so what kind of transportation is available in the early morning? and how long does it take to reach the airport?

Thanks in advance.

At that hour you will need a Water Taxi. The hotel can arrange a booking. The cost is about 80 euros, but that can vary ( they actually do have meters ) and the time from San Marco is about 30 mins. The Dorsoduro is also an excellent district and worth considering.

You could also take a vaporetto to Piazzale Roma and then catch a cab (or a bus, not sure if they run that early) which might save you some money if the water taxi is not within your budget.

Many many overseas flights leave Venice that early so yours is not a unique situation. At that hour most people have their hotel arrange a water taxi for them.

It's amazing how many people do seem to have that very same problem in Venice. All the public bus schedules are available, though, via internet. Look here for example: http://www.atvo.it/airport.php?ld=or...htm&id=1-0 - as you can see, the first direct bus from Venice, Piazzale Roma, arrives at the airport at 5.20 in the morning, so you aren't facing any problem with a 6.30 departure, and the cost is just 3 euros per person, luggage included. Vaporetti keep going, if rarely, all night through, so no problem to reach Piazzale Roma (from whichever town quarter) in time, too. For further boat and bus schedules, see http://www.actv.it/