Coral Spawning Great Barrier Reef

Where to experience coral spawning on the Great Barrier Reef

Each year, around the full moon in November, the world’s largest synchronised coral spawning event happens along the Great Barrier Reef

The spectacular display is proof of the future, the development of the next generation of this miraculous tiny animal.

In 2019, the spawning event took place over two nights in the northern region of the Reef, with soft corals spawning on September 16 and hard corals following up the next night on September 17.

But what exactly is this gigantic underwater snowstorm, and how can you go and experience it first hand?


Coral spawning really is the biggest reproduction show on Earth. And as inquisitive humans, we love to watch.

Once a year corals simultaneously release eggs and sperm bundles (spawn) into the water. These bundles then rise slowly to the surface where the fertilisation process begins. If successful, the fertilised eggs will settle on the ocean floor, eventually developing into coral.

The spawning can last a couple of hours or a few days.

With the health of the Reef continuing to make headlines, the interest in coral spawning has never been so high. This year’s event is predicted to be one of the biggest in recent years.  

How did the 2019 coral spawn go?

Marine biologists Stuart Ireland from Calypso Productions, Gareth Phillips from Reef Teach and Pablo Cogollos from Sunlover Reef Cruises were based on the Sunlover Moore Reef Marine Base to capture photos and video of the night-time coral spawning.

Stuart, having filmed the event every year since 1996 knows a good coral spawning when he sees it and rates 2019 up there as one of the best.

“The corals are really looking spectacular since the bleaching events of 2016 and 2017,” he said.

“There was coral spawn everywhere last night. It was like a grey haze with beautiful pink bundles going up – it was a magical night.”


Coral Spawning Great Barrier Reef

Well, see that’s the interesting thing. No-one knows exactly.

Sure, marine scientists can predict a rough timeframe, but they’re never going to put their house on an exact time and date.

Scientists at Townsville’s James Cook University only discovered the coral spawning phenomenon for the first time in 1981, so while research around it has developed since then, it’s still impossible to say exactly when it will occur.

Generally, coral spawning takes place between November and December in the northern Great Barrier Reef.

This year, the spawning is predicted to occur around November 15-18.

However, spawning happens later on the southern reaches of the Reef. This year it is expected to happen around late December.

It can also occur at different times depending on how far out on the Reef you travel.


There are several environmental factors that affect when coral are likely to spawn:

  1. The ocean temperatures must be 26 degrees or above for the month before for the eggs to mature enough.
  2. The coral will reproduce three to six nights after the full moon in November or December (in the northern Reef) when there’s less tidal movement.
  3. Spawning is also most likely to take place at least three hours after sunset when all plankton feeders are sleeping, giving eggs more time to settle into the safety of the Reef.


Coral spawning can occur between Heron Island to the south, and Port Douglas to the north, across a distance of 1000kms.

If you want to be among the action, your best chance of seeing coral spawning is by heading out on a dive boat from Cairns.

Operators like Tusa Dive, Divers Den and Pro Dive all offer night trips out to the Reef for coral spawning. These trips are suitable for divers, snorkellers or just keen observers. 

After the experience of a nighttime visit to the Reef, extend your stay in Cairns to see some of the famous dive sites during the day.

You can also take a four day/three night liveaboard boat out of Townsville with Adrenalin Snorkel and Dive. You’ll enjoy up to three night dives to see the spawning, as well as having the chance to visit other sites during the day like Lodestone Reef and Keeper Reef.

While the Whitsundays region isn’t renowned for its coral spawning viewing opportunities, there’s always the chance it could be the place to see it this season. Charter your own yacht to head out and see if you can witness the magic. 

Just by visiting the Reef you’re helping to contribute to its long term health.

A portion of the cost ($6.50 per adult) of visiting the Reef with a tour operator goes to the Great Barrier Marine Park Authority, who manages the Reef and its conservation.


Rather not go on a boat at all?

You can see the spawning from an island resort on the Reef. One of your best opportunities is on Lady Elliot Island.

Though they don’t run specific coral spawning night dives, if you’re on the island during the event it’s easy to see the spawning.

If the tide’s high enough you can see it night snorkelling in the lagoon. Or keep dry, thanks to a night time glass bottom boat tour during the spawning. There’s also night diving available just offshore from the resort.