The 1989–90 Courage League National Division Three was the third tier of English domestic rugby union competition for the 1989–90 season. It formed part of the Courage Clubs Championship, the national league system introduced in 1987 and sponsored by the Courage Brewery. The division sat below the Courage League National Division Two and above the regional leagues that comprised the fourth tier of English rugby.
The season ran from the autumn of 1989 through the spring of 1990. Participating clubs played each other on a home‑and‑away basis, with league points awarded for wins and draws. The structure of promotion and relegation mirrored that of the higher divisions: the top two clubs at the end of the season were promoted to National Division Two for 1990–91, while the bottom two clubs were relegated to the appropriate regional leagues (North or South) for the following season.
Specific details such as the complete list of clubs, final league table, points totals, and the identities of the promoted and relegated teams are not provided in the readily available encyclopedic sources. Consequently, a comprehensive statistical record of the 1989–90 National Division Three season remains limited in publicly accessible references.
