The 'wonderful and unusual' heyday of an island's underwater observatory
SOURCE:ABC Australia|BY:Vanessa Jarrett
It was once a star attraction alongside Great Keppel Island, with hundreds of tourists daily in the 80s and 90s, but these days snorkellers and fish are the only visitors.
"G'day, Coral here."
That's how Coral Wedd would answer the phone in the 1980s at the Middle Island Underwater Observatory's souvenir shop in the Pacific Ocean off Queensland.
"Not very many people go overseas to work each day under water by the name of Coral," Ms Wedd, formerly Howes, laughed.
Coral Wedd worked at the Middle Island Underwater Observatory from 1980 to 1982. (ABC News: Vanessa Jarrett)
"Coral would go to work under the water selling coral to the tourists."
It still makes her chuckle 40 years later.
"The typical day was the envy of everybody I think," she said.
"It was a wonderful time working on the observatory, it was an unusual time."
Great Keppel Island is 24 kilometres off the coast of Yeppoon in central Queensland.
Hundreds of tourists would fill boats and cruise along the Keppel islands, visiting the underwater observatory along the way. (Archives)
In the crystal-clear waters not far from the island, the Middle Island Underwater Observatory was a star attraction in the 80s and 90s.
"Hundreds of tourists … would come down daily from Rockhampton to the Capricorn Coast, they would load onto the tourist boats … probably 200 people each," Ms Wedd recalled.
Three fathoms deep into the sea, it even once hosted maritime nuptials.
The wedding of Mark William Heslin to Sharee Anne Newland was held in the underwater observatory on October 11, 1980. (Image: ABC Capricornia/Vanessa Jarrett)
A month after the underwater observatory opened in 1980, souvenirs from the gift shop were moved aside to make way for guests and a wedding party.
Mark William Heslin and Sharee Anne Newland tied the knot underwater on October 11, 1980.
"It was quite a novelty for the underwater observatory," Ms Wedd reflected.
The Middle Island Underwater Observatory was quite innovative and new at the time. (ABC News: Vanessa Jarrett)
In a sad but poignant affair, she also recalled when a young man's ashes were laid to rest.
He had visited the underwater observatory in the months prior and was fascinated with the set-up and the fish, she said.
Through an unfortunate accident, he passed away and his parents asked if his ashes could be buried nearby.
"Our diver from the observatory took the ashes," Ms Wedd said.
"The parents stood and watched as he planted the ashes under a rock and in the sand.
"It was a bittersweet day for his parents … that was the first, too, for the observatory."
A rare kind of tourist attraction
The opening of the Green Island Underwater Observatory in 1954. (Supplied: Quicksilver Group)
Australia was home to the world's first underwater observatory stationary structure in 1954 at Green Island off Cairns in Far North Queensland.
Built from an old Navy dive chamber, the observatory — which attracted a visit from Queen Elizabeth II in 1970 — closed in 2012 after being deemed unsound.
Queen Elizabeth II and the Duke of Edinburgh with Vince Vlasoff on Green Island’s Underwater Observatory, 1970. (Supplied: Sylvia Card/Cairns Historical Society)
Today, the world's largest underwater observatory is at Busselton Jetty, in Western Australia, built in 2003 with a 9.5 metre observation chamber.
A historic photo of the Middle Island Underwater Observatory, potentially the opening day on September 25, 1980. (Archives)
The Middle Island Underwater Observatory was the largest in Australia when it opened on September 25, 1980.
It was the dream of Yeppoon man Jim Nimmo, with the support of his wife Sheena.
Ms Wedd was there for the opening day, which involved much fanfare.
The souvenir shop on the ocean floor of the underwater observatory. (ABC News: Vanessa Jarrett)
"Lots of broadcasting, radio and TV, very important people coming across, lots of people there, all excited to see it," she said.
"Interestingly, the most excitement was from the dignitaries that came up from Brisbane, they were quite fascinated with the construction, the transport, the sinking [of the observatory under the water]."
Electrical current to prevent corrosion
The Middle Island underwater observatory under construction in the harbour. (Supplied: Capricorn Coast Historical Society)
The structure was built on land by Yeppoon firm, Goodies Engineering, between 1979 and 1980.
It was filled with 500 tonnes of ballast, made of copper and ilmenite.
The material was loaded via a giant funnel and crane at the Rosslyn Bay Harbour.
To prevent corrosion, the structure was designed that an electrical current would pass through it 24 hours a day.
The observatory was dismantled and taken to Farnborough Beach to be floated on the high tide. (Supplied: Capricorn Coast Historical Society)
The structure was floated out to sea and was set down 6 metres below sea level on plated piles driven into the seabed.
A Taiwanese shipwreck and other pieces of junk were sunk at the same time to create a habitat for marine life.
The 10-metre wide building had a souvenir shop on the ocean ground floor with 14 windows that looked out to the ocean.
An operator would feed the marine life twice a day to keep them lurking close by while tourists watched in awe through the windows.
Visitors would look out the windows and see the marine life outside. (Archives)
"The windows of the observatory were the only ones of their kind, they were 6 foot long, not the little portholes that most of the observatories had at the time," Ms Wedd said.
"I think that was the only one of its kind to have a tourist shop under water, in Australia anyway."
'Current state to be assessed'
Following the closure of the Great Keppel Island Resort in 2008, the underwater observatory was shuttered as well.
These days, the only visitors are marine life and scuba divers or snorkellers.
The area has been rezoned as a green zone, meaning no fishing can take place, which has in turn created a thriving marine life population.
Coral has formed over the old structure and sea animals use the nooks and crannies as a habitat.
It has become a popular spot with reef fresh, cod, groupers, sharks, rays and turtles often sighted.
The future of the site now lies in the hands of the state government, which rescinded the leases from former Great Keppel Island Resort owners, Tower Holdings, in 2023.
Earlier this year, a tender was awarded to a demolition company to clean up abandoned buildings on Great Keppel Island, and as part of the works, an assessment was to be undertaken of the Middle Island Underwater Observatory.
The Middle Island Underwater Observatory, pictured in January 2026, sits abandoned but is popular with snorkellers and divers. (ABC Capricornia: Vanessa Jarrett)
In a new statement requested by the ABC, a Department of Natural Resources and Mines, Manufacturing, and Regional and Rural Development spokesperson said the condition of the underwater observatory was still under assessment.