Cave Reef or Umm Chararim / Umm Khararim lies to the East of Zabargad Island and is half way between Gota Sataya in the South and Milkawa Island in the North. You are unlikely to be on your own when your on this reef. It is one of the most popular dive sites in St. John's Reef complex and you are likely to find one or two other liveaboard vessels sharing your space.
If you can convince the crew to stay overnight, you will get the chance to dive it first thing in the morning, ensuring extremely clear visibility. However, the best time to dive is around late mid-morning to early midday when the sun directly shines through the cracks in cave ceilings giving it a magical feel as the light cuts through the water.
Diving is fairly straight forward, the eastern side of the complex has larger passages allowing an easy swim through into the coral garden in the middle of the reef. The western passages are tighter and more complex to navigate - we recommend doing these with a guide to ensure not getting lost - there are a number of cross passages and tight dead ends which makes this section a bit more dangerous to dive.
However, the whole cavern system is very shallow, somewhere between 3 and 15m. This creates a significant up and down profile of your dive, especially at shallow depth, often creating havoc with your ears. Don't be alarmed if you get a reverse block, which on this dive can happen - just find the nearest exit with your buddy and make yourself "slowly" to the surface while diving along the outside of the reef back to you dive boat.