elan
Contributor
You'll probably find that trying to do 3 dives on a dayboat from Cairns will be hurried. The crew will be is a rush to get you in and out of the water, surface intervals and NDLs will be short, oh and it will cost more than two dives (except for the offer APS mentioned). I'd recommend going for the 2 dive option, you'll be more relaxed and there is a good chance the boats will only visit 2 locations anyway.
We paid 20 extra for the 3 rd dive
The diving on some reefs is like a ever lasting safety stop. Most of the fun stuff is in rhe top 20 ft. Some dives we were doing lasted an hour at least.
Yes it was on 2 reefs but still