As you swim down and through the arch, you will notice it is encrusted with sponges and soft corals, and ahead you will see a reef consisting of huge boulders of limestone, covered with soft reef life, starting at around 12m on the right and sloping down to around 40m on the left. At around 40m, the reef turns into a sheer wall which drops to around 70m.
The reef is full of life; from shoals of bream, parrotfish and wrasse swimming around it, the holes between boulders make perfect hiding places for octopus, grouper, moray eels and lobster, and where the sheer wall starts at 40m, large predatory fish such as bluefin tuna and amberjack are often seen. There is also plenty of life for the macro-photographer including fanworms, nudibranchs, and a plethora of other life on the reef.
Open Water divers will follow the reef around at 30m, Advanced divers at up to 30m, in a semi-circle. Eventually you will reach a wall which ascends all the way to the surface in front of you. Following the base of this wall at around 12m, you see a deep crack in the rock face. This is the entrance to a tunnel-like cavern (not an overhead environment - there's always air above) with 2 exits. Swimming through the crack and into the cavern, you will notice a beautiful dark blue light projected from the other exit. The walls are covered with an amazing array of colour which are soft corals and sponges. Swimming 20m through the cavern brings you out through the other exit at 14m with a wall on your left.
Following this wall brings you back to the base of The Arch, which you swim back up through to finish your dive making a safety stop on 5m on your swim back to the boat.
One of the nicest caves in Zakynthos also lies on this site - The Shrimp Cave. Due to its depth (30m) and overhead nature, this dive is suitable only for advanced divers with at least 50 dives and overhead experience.
The dive begins the same as above, but instead of following the cliff, you swim out to sea. You follow the reef down a slope to the top of a steep wall at 16m which drops to 35m. Swimming along the top of the wall, you come to a deep crack in the wall. Following this crack down to 30m brings you to the entrance of the Shrimp Cave, which looks like a huge crevasse in the side of the wall.
As you swim inside the cave, you will notice the array of beautiful colours of the soft corals and sponges on the walls. In the first few metres of the cave, you may be lucky to see flat-headed or spiny lobsters hiding in holes on the cave wall. As you swim deeper inside the cave you will see first tens, then hundreds, then thousands of translucent shrimps covering the walls and roof of the cave - a truly amazing sight. The cave slopes up slightly as you swim inside and towards the back of the cave, around 20 metres inside, you will see the darting black shapes of catfish which live in the cave as they make the most of your torchlight to hunt their prey - the shrimps!
You turn around and exit the cave, following the wall to the right at a depth of around 25 metres, although the wall drops in places to more than 60 metres. This steep drop-off is a good place to see the big predatory fish such as tuna and amberjack. Following the wall eventually brings you to the base of The Arch where, air supply permitting, you can make the dive as described above.