I. CZECH LAWN-TENNIS CLUB PRAGUE

This tennis club in Prague is located on Stavince island in the middle of the city.  It is very easy to get to the club, whether you are walking or taking the subway.  It was a short walk for us from Hotel Josef.  There are 14 outdoor clay courts and 10 indoor courts with a mix of clay and hard court.  This club was founded in 1893 and is one of the oldest and most prestigious clubs in the Czech Republic.
When you arrive at the club, you must ring the intercom and the club staff will let you in.  This club is beautiful with well manicured courts and clean locker rooms.  The cost for an hour is roughly 50 American dollars, but definitely worth it. 
http://www.cltk.cz/en/aboutcltk.php