By placing a user’s entire music library in the cloud, Apple’s iTunes Match service makes the Genius Mixes feature particularly useful, since these mixes now have your entire music library to choose from without potentially taking up a lot of space on your iOS device—tracks are downloaded and played on-demand as you listen to a given Genius Mix. This works great if you’re on a good Wi-Fi or cellular data connection, but users who are frequently offline or have limited cellular data plans may find this option less appealing.
Fortunately, the iPhone and iPod touch Music app do allow you to use your Genius Mixes offline, at least partially, by using any already-download portions of a Genius Mix and even allowing you to pre-download a Genius Mix on demand. Simply go to the Genius Mixes section in your Music app and you should see a small iCloud download icon in the top left corner of the screen.
Tapping on this will download 25 selected tracks from the current Genius Mix, making them available for offline listening. The Genius Mix will also include any additional tracks that have already been downloaded to your device from other albums or playlists, or simply from normal listening; if the iCloud download icon doesn’t appear for a given Genius Mix, this means that there are already enough tracks on your device and there’s no need to manually download additional tracks to listen to the Genius Mix offline.