In a statement to the Athens bourse yesterday, J&P told investors that its subsidiary Athena had signed the deal this month to build, operate and maintain the marina which is thought to lie on the south side of Yas Island.
J&P said the work involved building a floating pontoon system from which to moor boats, and a boat launch slipway.
The Marousi-listed company added that it would also construct roads around the new marina and infrastructure including street lights, traffic lights, pumping stations, tap water and a telecoms network.
Construction work is scheduled to take 28 months and J&P has also agreed to operate and maintain the project for two years after completion.
The original Benoy Architects master plan for Yas Island includes six marinas with a total of 1,500 berths.
The first, Yas Marina, overlooking the Formula One circuit, currently provides 175 berths that cater for boats between 8 metres and 150 metres.
According to the master plan, the Yas Cays Marinas have been designed as four linked marinas on the south of the island, which will provide a total of 900 berths and be linked to two major new housing schemes.
The remainder of the berths will be located in the Northern Marina on the north side of the island.
J&P, which helped to construct the original Abu Dhabi International Airport in 1981, said that it had also recently signed a 30.1m contract with a consortium building a nuclear power plant in the UAE.
It said work to build a quay wall to provide shore protection and other marine works was already under way and would be completed within 20 months.
Aldar was unavailable for comment.