Prague daytrip to Vienna

I would not. First: there is enough to see in Prague in 4 days to keep you busy and second: round trip takes 9 and half hours, add trip to the station and from the station and how much time you have got left for sightseeing in Vienna? It would not be worth your time and money.

Thanks llja, from your explanation, we would just our 4 days in Prqgue.

Vienna is too far but I would look into some shorter day trips in the event you get bored in Prague. Four days is great for some and pushes the limits for others.

Vienna is one of those one week desinations. There's too much to see in only one day's visit. And the train ride between the cities is pretty slow.

Thanks David. After the feedback that I got here, We decided that Vienna will not be a good day trip.
We plan to visit the castles like Karlstjen instead .Just have to read up more regarding how far it is and how to get there.

Karlstejn is forty minutes by train from Prague Main Train Station. I checked the morning schedule. Train goes every 40 minutes. You can find the schedule on Deutsche Bahn schedule or on http://www.idos.cz .