Vienna transportation

I'll try to help you onto the right track.

The RJ and S7 trains run every 30 minutes respectively from the airport to the city, i.e. there is a train departing every 15 minutes. Just board the next train, so you won't waste time waiting.
If it is an RJ train, go to Wien Hbf (main train station), take the U1 subway (red line) to Stephansplatz.
If it is an S7 train, go to Wien Mitte, take the U3 subway (orange line) to Stephansplatz.

I recommend buying all necessary tickets online in advance, obtain them as pdf files, print them and carry them with you. So you avoid any hassles with the ticket vending machines, saving valuable time.

For Vienna you correctly chose the one day ticket (€5.80 each), i.e. €11.60 in total.
https://shop.wienmobil.at/en/products/ONE_DAY

As a bearer of the one day ticket the ride to/from the airport is only €2, i.e. €8 in total.
https://shop.oebbtickets.at/en/ticket
Buying these tickets is a bit tricky. You must choose the approximate time slots, and when selecting "adult" the default will be "without discounts". You must click on "change", "add discount", expand the drop down menu, click on "Ticket Stadtverkehr Wien (Kernzone) ". (I guess that is deliberately so complicated just to make more profit.)

Therefore: Transportation €19.60 for 2 for the day.

Thank you!!

When I purchase my tickets to and from the airport, is the time I purchase the ticket for important? I don’t know exact times.

Choose trains having departure times you most likely expect to travel. These short range tickets are valid for two hours, and you can use any train, not just the one you had selected during the purchase procedure. Don't worry about being late. I never had problems, and most of the time the tickets are not checked at all.

Hi. Vienna is great and transportation system is excellent. Good advice above from wmt1. But also, fyi, if you find buying the tix online confusing, easy to just buy your tix from a machine at the airport right before you board the train to the city. Enjoy!

Or take a taxi one way it probably won't force you to declare Bankruptcy

Hello from Vienna! I know you are here today but in case you are reading this message, the Belvedere is across the stress from the Hauptbahnhof. You can walk, no need to take the D.

When you arrive, you can also take the RJ train from the airport to Hauptbahnhof and then get on the U1 to Stephansplatz. Basically, just take the first train from the airport into the city - either S7 or RJ. Both will take the same amount of time to get you to Stephansplatz.

Also, if you have the day pass, then when you buy the ticket to the airport, you can check the box that says Ab Stadtgrenzone which will save you each 2 Euro as that gets you to the Vienna border (which you have already paid for with your day ticket).

Headed back to the airport after beautiful day in Vienna. Thank you all for your help! 😃

@Emily
Did you happen to notice my first post answering OP's questions? :-)

... if you find buying the tix online confusing, easy to just buy your tix from a machine ...

@Bob
Certain tickets, e.g. the One Day Ticket or the Flexible 7-Days Pass, must be bought online, i.e. they are not available from a ticket vending machine or ticket counter.

Wmt1 - I saw it after I posted!