Illawarra will have all four District women's pennant champions in the state finals following brilliant wins by Thirroul and Dapto ladies in their regional playoffs.

Illawarra Grade 3 champions Thirroul and Grade 4 winners Dapto scored comeback victories over Southern Highlands champions Goulburn in thrilling finals at Picton Bowling Club.

The clubs join reigning Grade 1 state champions Warilla and Illawarra Grade 2 winners Shellharbour to qualify for the state finals in a memorable season for the Illawarra District.

Thirroul and Dapto supporters ensured a great atmosphere at a chilly Picton, with both regional finals producing outstanding bowls under intense pressure.

Thirroul delivered the performance of the year to rally from 18-10 and 24-17 down on 26 ends to claim a draw and force the Grade 3 playoff into an extra end.

Spurred on by their supporters, Thirroul booked a place in the state playoffs by picking up seven shots across the two rinks on the extra end.

Mary Rodgers' team picked up four shots and Dianne Hamilton's team three shots, with the Thirroul players swamped by supporters after the final bowl was played.

Meanwhile, in Grade 4, Dapto also completed a remarkable comeback triumph after trailing Goulburn 18-10 on 18 ends and 24-17 after 26 ends.

Dapto refused to concede and finished too strong over the closing ends to win 33-31.

While Warilla head into the finals as defending champions having four teams in the playoffs is a major achievement for the Illawarra District.

With Shellharbour Bowling Club closing it will be the last time its players bowl together as a team, while for Thirroul and Dapto, making the playoffs exceeded expectations.