On my trips to Heron Island in June 1989 and later in October 1989 for the Heron Island Dive Festival, I dived Hole in the Wall three times. Once was as a stand-alone dive but the other two were drift dives from Hole in the Wall to Coral Grotto. This article is about the drift dive.
Like the majority of the dive sites at Heron Island, Hole in the Wall is located on the eastern side of the reef. It is east-north-east of the northern tip of the island. Coral Grotto is located to the north-west of Hole in the Wall.
|A map of the dive sites of the northern side of Heron Island
Click to enlarge
Note this map was drawn in 1990 by Clarrie Lawler - used with his permission
The actual Hole in the Wall that gives its name to the dive site is not at the mooring location (well, at least it was not in 1989) but a bit to the north-west. The mooring is located on one of a twin pair of coral bommies located about 20 metres off the main reef.
|A very rough map I drew of Hole in the Wall to Coral Grotto in 1989
Note depths are in feet - Coral Grotto is at left
Once you descend, drop to the bottom of the twin bommies and circle around them. The depth here is about 15 or so metres. There can be some interesting life in the small canyon or crack that separates the two bommies. From here head south-west to the wall. You will see that there is a small bay to the south of you as you approach the wall. This can be explored towards the end of the dive. You may also notice a swim-through that goes from outside the main wall to the bay. You can swim through this and then go back to the outside of the wall.
If you do not do the swim-through, turn right once you hit the wall and follow the fringing reef wall. This runs in a roughly south-east to north-west direction. The depth at the bottom of the wall is about 10 metres (I think - my map does not show what it was). The wall is relatively straight till you come to an inlet. Just past here you will notice that the reef comes to an apparent dead end and there is a small bommie in the bay.
The reef wall actually doubles back on itself in a U fashion. However, you do not need to backtrack as there is another way out. This is via the Hole in the Wall. In fact, there are two Holes in the Wall. As you start to do your U turn and follow the wall back in the same direction you have just come, you will see a swim-though on your left. You can easily swim through this and exit on the open ocean side of the reef. Alternatively, you can do the second one or swim around the point and end up again heading north-west.
Once back on the main wall, you are about two thirds of the way to Coral Grotto. Just about here you will see a larger bommie off the wall and then a small bay in the wall. Past the bay there is another bommie off the wall and then another bay.
A short distance past here there used to be some star pickets (steel posts with an X cross-section used for fencing) that appear to have been installed to provide warning that the mooring for Coral Grotto is coming up. The mooring is actually located on a largish bommie off the wall and so if these star pickets are still there, head out 20 or so metres off the wall to find the bommie.
The bommie has the mooring on the top. Spend any time you have left around the bommie before ascending. Generally you will get over 60 minutes as it is not very deep.
This was one of the best dive sites I did at Heron Island. On one dive I saw 10 turtles, a white-tipped reef shark, a black whaler shark as well as Queensland groper and potato cod. In the swim-throughs I saw abalone and crayfish. Other things I saw included Moorish idol, yellowtail kingfish, sweetlips, flutemouth, fusilier, parrotfish and unicornfish.
Note this article was written in 2008 so my memory may be a bit out with some aspects of the dive site and things may have changed in the almost 20 years since I last dived there.