The Mercedes limousine was found in the popular Lake Pichlinger in five metres of water, according to a report in Kronen Zeitung.
It had been discovered during a routine dive by a pair of hobby divers. There was no body found inside the vehicle.
It is suspected that the vehicle had been stolen from nearby Linz. A similar case occurred with a stolen vehicle in the same lake in May.
Police suspect there may be a link between the two cases, and reported that the investigation is ongoing.
In the previous case, passers-by had discovered tire tracks leading down into the lake.