This is what I do:
First you will need to check the root of your phone for 2 folders. One names "Music" and the other "Playlist". If not there then just create them.
1. Sync WMP playlist with a flash drive or any way that will get you all of the songs on that playlist simple and fast.
2. Copy all those songs to the "Music" folder on the root of your SD card.
3. Select the Playlist on the side panel of WMP right clicking and select "open file location" and then copy that playlist file to the folder "Playlist" on your phones memory.
You're done. Your playlist should be synced in the same order as on WMP and should show up on the default player of Android. I use a flash drive to store music for my car and I sync it once in a while so then you could just copy all those songs once synced to the flash drive and the new songs will appear and just click "don't copy repeated files", what you will mainly need to redo again is copy the Playlist FILE from WMP.
Note: I have a Galaxy S and all this was done using the INTERNAL Memory and the DEFAULT Android Music Player. Not sure if it will work with external SD card but I don't see why not.
Wow!! I know this is a very old post, but I've boon looking for a way to do this for years and had concluded it was impossible. It was this simple. I had tried syncing the WPL through Windows Media Player (over USB), which did not work for me. That sync'd the songs, but not the Playlist. But the incredibly simple step of just dragging and dropping the WPL file(s) to the Playlists folder on the Android device immediately made the Playlist available and it worked with the songs (already sync'd via Windows Media Player).
So if anyone is still looking for a way to do this even on Android 11 in 2022, here are the steps:
1. Connect Android phone to PC via Bluetooth
2. Swipe down and scroll to the bottom of the notification area and set USB connection to "File Transfer" (as of Android 11, this name has changed with different Android versions). This is necessary so that your PC can see the file store on the phone, otherwise, it won't have access (some of the posts above asked about this).
3. In Windows Media Player click on Playlists on the left.
4. Right click on one of the Playlists and select "Open file location" This will pop open an Explorer window with your Playlist(s). Set this aside for later (Step #8) and go back to Windows Media Player.
5. Click on the Sync tab in the upper right
6. Drag the Playlist(s) in the main window over to the Sync area on the right (see screen show below)
7. Hit "Start Sync" right below the tabs and above the Playlist(s) to sync. For me, this only synced the Songs, NOT the playlist, but that's OK (thanks to kcinholas's post)
8. Click on the Windows Explorer window you opened in Step #4.
9. Open another Explorer window (Windows+E or from the Taskbar or Start). Navigate to your Android device (be sure it's still connected via USB and in File Transfer mode).
9. Open the Android device's main drive/volume, probably called "Internal shared storage" (not sure how this would work with an SD card, but I assume that can work and the process is similar)
10. You should see several folders at the home directly of the device, including Music and Playlists. Open Playlists.
11. Drag and drop any Playlists from the Windows source to the Android destination.
Summary:
1. Sync music from Windows to Android over USB via Windows Media Player. You can sync individual songs, albums, or artists, or by Playlist, but syncing a Playlist through Windows Media Player will only sync that playlist's songs, not the Playlist itself.
2. Copy (can't sync) the *.WPL Playlist from Windows to the Playlists folder on the Android device via Windows Explorer.
That's it!
Windows Media Player does smart syncing, so even if you have dozens of GB of music, adding a few new songs will still only take a few seconds.
Thank you, kcinholas!!