Umm Aruk

A typical plan starts on the east side late in the morning. Divers pass the two boulders that reach the surface, turn into the maze of towers after the second one, crisscross the blocks heading north, and come back along the reef edge to the boat.

The Zodiac variant begins in the northern lagoon, where young whitetip reef sharks sleep in the sloping grooves, then runs out to the older animals. It continues around the blocks and west to the garden eels and eagle rays, and follows the jagged wall to a channel where Napoleon wrasse pass. Where water layers of different temperature mix between the blocks, the water shimmers.

From the surface, a reef of 200 by 250 m is hard to credit. Behind the two boulders on the east side stand about two dozen free-standing towers, 6-9 m high and 2-4 m across, and the west side adds more boulders and towers shooting up like mushrooms. One operator ranks it the most interesting reef of the St John's area for this maze.

Corals and fish compete for the best spots on every block, and the north side holds bannerfish and lemon butterflyfish in large numbers.

The current is unstable and can come from any direction: south-west in the morning, north-east at midday, south-east in the afternoon. Hold your heading between the towers and use the swirls between the blocks to your advantage.

The boulders reach the surface, while the main dive runs 25-27 m. Plan on 20-30 m of visibility and a 5 mm full suit.