Many dive wrecks are located at depths below 18m so an Advanced qualification is needed. And if you want to go inside wrecks, you need to be a confident diver and it is worth looking at doing a wreck diving specialty course. In terms of equipment, all you really need is a torch as it can be dark inside the wrecks. And a GPS to find them!
Charlie, Original Diver
Though in this day and age you are highly unlikely to discover a lost shipwreck laden with Spanish doubloons, rusty chests full of rubies and pirate booty, wreck diving still presents one of the most exhilarating and unique experiences for divers. It involves a dive targeted at a sunken vessel which could be anything from an intentionally sunken rig to a World War II battleship. Wrecks often act as man-made reefs, and are home to an abundance of fish seeking shelter from predators, so an ideal place to see unusual or elusive species of marine life.
Depending on your level of certification, you will be able to experience wreck diving in different ways. To enter enclosed spaces within vessels you will need to have at least an advanced certification as structures can often be brittle, imbalanced or unstable, with poor visibility.