Townsville may be an option. I live here and it's a lot less touristy than Cairns but still has access to the Great Barrier Reef. There are liveaboard options with Adrenalin Dive and Remote Area Dive do a weekend dive safari on Pelorus Island. Most of the dive shops do day reef trips including ProDive and Pleasure Divers. Also if you decide to do the AOW you can dive the Yongla Wreck which is said to be the best dive in Australia and often makes the list of the best dives in the world. In fact in [this list](Townsville may be an option. I live here and it's a lot less touristy than Cairns but still has access to the Great Barrier Reef. There are liveaboard options with Adrenalin Dive and Remote Area Dive do a weekend dive safari on Pelorus Island. Most of the dive shops do reef trips including ProDive and Pleasure Divers. Also if you decide to do the AOW (I'm doing mine this weekend!) you can dive the Yongla Wreck which is said to be the best dive in Australia and often makes the list of the best dives in the world. In fact in this list the Yongala and Magnetic Island are mentioned! (Magnetic Island being a 20 min ferry from Townsville).