The reef, made from sand filled bags, acts as a ramp which will change the way the waves break, improving the quality of the surf.
New Zealand-based reef consultant ASR is undertaking the project, which is worth £2.7M.
The eastern-end of the reef was attached to 5t anchors on the seabed by a team of divers. A barge was then winched along the reef site, allowing the section to unfold into the water.
Winches then pulled down the reef onto the seabed and divers secured it in place.
Each of the 16 bags that make up the first section of the reef are now filled with sand dredged from the sea. Then the remaining four sections will be deployed and filled.