Google Maps is a great navigation tool on Android and so far competition has either been lame or inexistent. But that has changed with Nokia making its popular Here Maps available for Samsung devices first, and for other Android devices recently. Don't go look in the Play store, you won't find it there. Here Maps for Android is still in beta and can be downloaded on Nokia's official Here site.
Since you will be downloading a file outside the Play store, make sure "Unknown sources" is enabled in your phone settings. If it is not activated, your phone will offer to take you there after you tap the download link. Once the download is complete, go ahead and install the app.
Tap the Hamburger inside the app (that's the three horizontal lines stacked upon each other) and tap "Download maps". In order to download, you must sign in with a Facebook or Here account; A sign up link is also available. After you authenticate, the app will get a list of maps. Tap "Download new". Select Africa > Mauritius. The file is 126.4MB in size, double the size of the Windows Phone version.
I will compare how Here Maps work on Android and Windows Phone in another post.
Enjoy offline maps of Mauritius.