Why don't I see any leagues in Explore?

Explore shows leagues whose host city falls within your search radius, the same way games are filtered, and if there are no leagues near you the Leagues section is simply hidden.

When you are signed in, Playbox lists published leagues whose season is still running and whose city sits within your personal search radius. Unlike games, leagues have no worldwide fallback for signed-in users, so when nothing is in range the section does not appear at all rather than showing distant leagues. Guests who have not set a location still see a global shortlist.

If you expected to see leagues, try widening your search radius so more cities are covered. To make your own league discoverable, publish it (not draft) and it will appear to players whose radius covers its city.