Illawarra needed to win the season-ending clash to snatch a spot in the six-team finals series.

But they endured a horror shooting night, connecting on a dismal 4/28 three-pointers (14 per cent).

After leading 13-4 early, the visitors were overrun, falling behind 22-19 after one quarter and 46-38 at half-time.

They faced a 69-60 deficit after the third period and never seriously threatened down the stretch.

"We played fairly well in terms of energy, effort and defence, but we didn't shoot the ball well," Illawarra coach Matt Flinn said.

Dan Jackson led the Seahawks with 24 points and Dom Cooks had 19.

Troy Pilon finished with 14 points and 14 rebounds and Keiran Gleeson worked hard for his nine points and 16 rebounds.

Leading the scoring for the home side were Stefan Blaszcynski (24), Tim Hudson (18) and Terry Johnson (15).

"We did a fairly reasonable defensive job on their scorers, but (guard) Cam Fincher is our designated stopper and we missed his defence," Flinn said.

"He tried to play but his shoulder injury stopped him from getting after it with his usual intensity."

The Seahawks finished with a 10-10 record and Flinn was disappointed their campaign had come to an end.

"We played and trained hard, but it's fair to say this team underachieved on what we all thought would be a more successful season," he said.

"On the plus side, we gave a lot of young kids the opportunity to play at a high level. Dan Jackson, Dom Cooks and Brad Simpson showed they have big futures."