A great and huge pay-beach in Vienna, Gänsehäufel is worth the trip. I've tried other beach clubs…read morein Vienna and this one has them all beat with its large size, great facilities and food options, and nice beach along the alte donau.
Located on an island in the alte donau, you can get there from the U1 VIC stop via a free shuttlebus or a 10-15 minute walk.
Admission is just €5 for the day and €3.9 after 13:00. They have several pools, a diving one and a fun one for the kids. There are lots of trees to help offer some shade and reprieve from the sun. Several bakeries and snack bars help keep you fed during a long day of swimming.
Swimming in the river is nicer here than other beach clubs, because they have smooth stones living the river bottom for you to stand on. Other clubs make you stand in the mud of the river, which isn't very nice.