Last week, councillors closed their meeting to the public when they threw out the offer on the site previously used to garage mowers and trucks in the former quarry comprising 2B Nailsworth Street.
They instead decided to sell by tender in an attempt to get a better price this month.
Chief executive Carl Askew cited confidentiality last week when he was asked the amount that had been offered and the identity of the interested buyer.
The depot’s eventual sale has been mooted to potentially generate about $13 million that the council could partially use for new Cottesloe Beach facilities, including toilets near the Indiana Restaurant and other foreshore facilities.
Selling the site may end a more than decade-long attempt to find a new role for the depot.
The council’s gardeners and road workers, with their vehicles, now use a temporary location in Fremantle after negotiations to use the McCabe Street depot operated by Mosman Park Council failed.
Any buyer of the Cottesloe depot could sell lots for up to 13 homes using an R20 subdivision plan recently approved by the WA Planning Commission.
The sale will now be advertised for 21 days before Mr Askew’s assessment of the resulting offers that are expected to be considered by councillors next month.