Welcome, Barbara! I'm looking forward to my June 21st PG cruise, so I feel your excitement. As for your question, while I've not yet cruised in that area. I spent two weeks split between Bora Bora and Moorea, and like others here said, you don't have to get in the water to enjoy gazing at it. You won't believe how beautiful it is. Something about the colors of the water and the sky and the flowers...little wonder Gauguin packed up and went there to paint. I hope everything you read here puts you at ease.

Oh! I've traveled to Auckland and Sydney (extensively) and you will love these cities. Bring warmish clothing/layers as it will be winter-spring there (did you say Sept? I forgot). Temps might be damp 60s, depending.