Hi, I had to reset my Fenix 5+ during a trip and lost all music I transferred when I hooked up my fenix with my laptop back at home. I do not have access to a PC or laptop (that I trust) now during my vacation....how can I transfer my mp3s to my Fenix using my android phone (where all my music is stored)? Thanks for any hints...!
At this point you would have to download from a third party provider (spotify) to get music on your device. To do what you want to do you'll need Garmin Express/USB Cable on a PC or Mac.
Unfortunately the 5 Plus has MTP transfer only, so regular file transfer from a phone with an OTG cable doesn't work. There are apps to enable USB MTP, but I never tried any of those myself. Older watches had USB mass storage mode (but no music).