A single coral colony stretching 100 meters (328 ft) along the Great Barrier Reef, the longest-ever documented, was recently discovered by a mother-daughter team of citizen scientists.

World’s Longest Coral Colony

Sophie Kalkowski-Pope, Marine Operations Coordinator at Citizens of the Reef, and her mother, Jan Pope, stumbled upon the find while taking part in the Great Reef Census, which tracks the health of the Great Barrier Reef (GBR) off the coast of Queensland, Australia.

“I knew right from the minute we dropped in that it was something special,” said Kalkowski-Pope in a statement.  “When I got in the water, I’d never seen coral growing like this before,” Pope said. “It looked like a meadow of coral. It just went on and on.”

Though the pair hasn’t come prepared with instruments capable of measuring something of this size, they used several approaches to estimate the size of 366 feet and the area of 40,000 square feet. That’s roughly the size of a standard football pitch for the world game.

Since their initial findings, the size has been confirmed using high-resolution imagery carried by boats. For scale, a coral colony in Solomon Islands, which was declared the world’s largest in 2024, is one-third of its size.

“The benefit of this kind of spatial data is that we can take measurements at very high resolution,” said Serena Mou of Queensland University of Technology. “It also means we can return in future months and years and make direct, one-to-one comparisons to understand how the coral changes over time.”

According to Citizens of the Reef CEO Andy Ridley, the colony’s ability to thrive is likely due to its location, which happens to be in an area with deep water and strong currents. “We had to dive it during the slack of the neap tide,” Ridley said. “We’ve found that where current flow is higher, corals seem to be more resilient.”