Howies Scuba

North of the river is open to the Indian Ocean and has no natural defences, no close to shore Islands or any peninsulas that gives you the same protection you find South of the River all but for one site, North Mole, which is protected slightly from the prominent SW swell. I have never dived North Hillarys' Wall or Mindarie Marina, but the potential appears to be the same for these two areas.

Generally South of the River dive sites are more stable and reliable as dive sites. This is due to the protection you are afforded by Point Peron and Garden Isl. from the SW swells that hit our foreshore. As it is part of the natural defences Point Peron does not get the luxury of this protection. The further north you move the lessening of this protective effect is evident.

If you are a little bit like me and are addicted to getting wet, then the cooler months of the year won't put you off diving regularly, even though it may slow it down a wee bit. Here is a list of dive spots that offer some protection when the swell is as tall as a house and the wind is whipping you red raw. They go from greatest protection to least protected. The main swell & wind  direction for Perth is predominantly SW. A strong Northerly wind will generally make these sites worse to dive.*** Also consider the river in most adverse conditions.

As far as I am aware, there are no sheltered natural limestone reefs. However you will be able to dive both Point Peron and BBR in stronger swells than that of the other sites covered here.  I have dived Point Peron in 1.8m swell and it was just about dive-able and BBR with a 1.4m swell which was a little silty and surgey. All other reefs require 1m or less swell, low Easterly winds, and a low swell period less than 11.5 seconds to dive it comfortably.

I can't say I know of any Jetties North of the river, except for Navy Pier, bit far though. I love jetty dives, everything confined to one spot, when Solo diving I hit Ammo Jetty most of the time, there is always something new to find, some little critter hiding in a little nook that you have never noticed before, brilliant. But my favourite site is Robbs Jetty, just bathed in sunlight, always a treat or two to find there.

There is an abundance of wrecked vessels along the WA coast, both along the shoreline or slightly further out requiring transport to investigate them. South of the river in Jervoise Bay was in by-gone days  used as scuttling grounds for Ships in WA, unfortunately most of these would of been wooden hulled and have longed disintegrated. Last but not least is old faithful the Wreck trail at Rokingham.

Generally I don't dive groins if I can help it. I will use the Groin at Jervoise Bay boat ramps when the weather is quite horrible. However groin dives are poor dive areas due to the fact that they obviously do not allow for the flow of water through them, which is very important for marine life and marine environments to flourish, most groins are silty murky areas. That said every now and then you will be treated to a nice surprise.