Gerrard Cunningham led the way for the Bombers with a bag of seven goals and Kristan Height bagged five.
It was a grueling first half with the Bombers heading into the main change leading by four goals.
The second half saw the reigning premiers put on a dominant display booting sixteen goals to two, putting fear through the rest of the competition.
Billy Barden and Albert Tipungwuti showed their class leading the way in the second half goal blitz.
The Bombers will now face off against Saint Mary’s on Saturday March 2 at TIO Stadium for a place in the NTFL Grand Final.
Tiwi Bombers 26.12.168
Southern Districts 9.7.61
Goal Kickers: G. Cunningham 7, K. Height 5, R. Tungatalum 4, D. Munkara 2, E. Darcy 2, D. Barden 2, A. Wonaemirri , S. Mungatopi, B. Palipuaminni , R. Kantilla.
Best Players: B. Barden, A. Tipungwuti, G. Cunningham, R. Pupangamirri, B. Palipuaminni, K. Height