Some boat owners have been waiting up to 19 years for a mooring at their preferred Rottnest Island location.
A boating management plan - released yesterday with a 20-year strategy for the island - showed there were more than 500 people on the waiting list for moorings.
The longest wait has been 19 years for one of the 62 moorings in Marjorie Bay at the western end of the island.
The shortest wait has been two years for Porpoise Bay, on the southern coast, where there are 30 moorings.
The plan said the proliferation of boat ownership in WA and the popularity of Rottnest as a boating destination meant "for some time" demand for moorings had outstripped supply.
There are 849 permanent licensed moorings and 41 rental moorings around the island. Thomson Bay has the most, at 280 moorings.
In 2011-12, only 43 mooring site licences became available and were offered to boaties on the waiting list.
The plan said the proposed marina - to be developed on the site of the Army Jetty in Thomson Bay - would include private pens to help meet demand from the WA boating community for suitable and protected moorings.
The marina would be designed to offer greater protection for boats of up to 25m in a range of weather conditions.
In his foreword to the plan, Rottnest Island Authority chairman John Driscoll said about 185,000 people visited each year using private or charter boats. He said the trend towards increased boat ownership and bigger boats was putting pressure on the Rottnest marine reserve.
"The authority values those visitors who use our facilities regularly, but to ensure the island meets its maximum potential as a boating destination, we want to attract new visitors, as well as encourage those who for some reason have stopped coming," he said.
The plan also revealed the island's main jetty had deteriorated because of sinkholes and concrete cancer and would need "significant ongoing capital commitment".