North of Cairns and northeast of Port Douglas, the snorkelling at Agincourt Reef on the Great Barrier Reef is considered one of the best snorkel dives in the world. The stands of elkhorn and staghorn coral in this ribbon reef provide habitat to marine life including sea turtles. During Agincourt Reef snorkeling, you may encounter unicornfish, clownfish, lionfish, giant clams, maori wrasse, garden eels and barracuda.
There are 16 distinct dive sites at Agincourt Reef. The water depth varies from surface down to 50 feet deep.
In addition to the diverse marine life, the Irukandi Jellyfish may also be present from November to April. This tiny box jellyfish is about one cubic-centimeter in size and is the most venomous jellyfish in the world. Snorkelers who have encountered the Irukandi Jellyfish have reported only a slight stinging sensation, and then 30 minutes later they have muscle cramps and nausea followed by increase blood pressure and heart rate. A sting usually requires hospitalization. A full-body stinger suit with hood is recommended from November to April when snorkeling here.
The Agincourt Reef is located 65km off the coast of Port Douglas. There are daily charter boats providing access from Reef Marina in Port Douglas.
Overall, Agincourt Reef is the 11th most popular snorkel dive spot of all 37 snorkeling dives in Queensland.