There were six participating teams in the Santam Bank Trophy Division B.
The top team qualified for the section finals, played at the home venue of the higher-placed team, as well as the Division B finals.
The Division B champion qualified for the promotion play-offs.
The winner over these two ties qualified for the 1989 Santam Bank Trophy Division A, while the losing team qualified for the 1989 Santam Bank Trophy Division B.
Northern Natal were initially relegated to Division B, but due to the Currie Cup Division A's expansion to 8 teams, they retained their place.