Some good places to listen to Mozart music online for free are the Saint Paul Chamber Orchestra, Last.fm and Jango websites, as of 2015. These sites allow visitors to explore a variety of songs by Mozart.
The Saint Paul Chamber Orchestra site does not require registration to listen to music. The site also offers music by other composers and musicians. Another good location for listening to Mozart's music is Jango. Visitors to the site can search for music by artist, genre or song title. The site also offers a free app for Android and Apple devices. Another location for listening to Mozart's music online is Last.fm.