Diving in Bali can be a great experience, but it does require some preparation. Unfortunately, some divers forget this, and so need to visit a dive shop in order to obtain all of the needed supplies. While there is no question that you can find everything you need, it helps if you know what you need before heading into a Bali dive shop.
Make sure that you go in with a checklist and you should be fine. While a wet suit is optional due to the warm waters, breathing gear is mandatory for any sort of long dives. Camera gear should also be debated, especially as you are going to want to grab as many shots as possible. Fishing gear should be debated, especially given local regulations on fishing, but gloves and gear for carrying items should be grabbed. Diving does not require much gear, but it does require some; if you do not carry it with you, make sure you know where to buy it locally.