Was up there for two dives in Dec/Jan. Recommend departing from Port Douglas and using smaller boats - suggest looking at Poseidon. The bigger boats such as Quicksilver pickup in Cairns but it takes about two hours to get up Port Douglas, whereas if you hire a car it's only a one-hour trip. Also the bigger boats take longer to get everybody into the water, thus you're usually restricted to two dives, whereas the smaller boats can squeeze in three dives. Both boat types usually operate from the same reefs. For more info, go to tripadvisor.com and look at the Port Douglas or Cairns forums.