In order for your release to show up under upcoming in your Spotify for Artists account it will need to be in Spotify's system at least one week before the release date.
We recommend uploading your release to DistroKid at least two weeks prior to your release date if you want a song to be available to pitch to Spotify's editors for playlist consideration.*
If you've uploaded your release with a future release date and it's still not showing up under upcoming it could be a mapping issue, where your music is mixed up with another artist's music.
If services ever put anything on the wrong page, you can always use our fixer tool to get things mapped correctly, but you can also reach out to us via our contact form with a link to your Spotify Artist URI and we can check to make sure that Spotify has your upcoming release(s) mapped to the correct page.
You also can’t pitch if you’re a featured artist on the song, so if it's a collaboration make sure you are listed as a primary artist on the release.
Check out this article for more info on how to setup a collaboration.
*Note: You have to have a Plus or Ultimate subscription in order to setup custom, future release dates.