The owners and operators of Hastings Pier have been convicted of breaching the Health and Safety at Work Act.
The pier partly re-opened in July after repair work was carried out
The Victorian structure in East Sussex was closed by Hastings Council in June 2006 amid fears it could collapse.
A judge at Hove Crown Court said if it had not been shut there could have been serious injury or loss of life.
On Thursday, owners Incorporated Ravenclaw Investments and operators Boss Management (UK) Ltd were fined £80,000 plus costs.
The pier partly re-opened in July this year after Stylus Sport, the owner of a bar on the pier, and Hastings Borough Council funded repairs.
The council had closed the central section of the pier in the interests of public safety on 16 June 2006 using emergency powers.
After the hearing, Kevin Boorman, a spokesman for Hastings Borough Council, said: "This is clearly a huge fine, and shows how seriously the court viewed the offences.
"As the court heard, we tried for several months to work with the pier owners, to no avail.
"Because of our concerns over public safety, we ultimately had no option other than to use our legal powers.
"Public safety has only ever been our concern, and this verdict, and fine, completely vindicates our position."
Talks to be held
He added that the council now needed to move forward.
Mr Boorman said: "In the absence of the survey carried out by the pier owners, we have commissioned a full structural survey ourselves.
"The physical work has been completed, and we are awaiting the publication of the survey."
He said the authority would then know the cost of repairing and maintaining the pier and would be able to talk with interested parties "with some confidence about the various options".