From notes I made for another couple going to Bonaire (we go for 2-3 weeks at a time):
You wont need as many clothes as you think. I pack 2 swimsuits (the kind that can double as shorts, not speedos), 1 or 2 pairs of khaki shorts,1 pair khaki slacks, 3-4 golf shirts, maybe a pair of blue jeans, a bunch (5-6) of T-shirts. I bought me some Champion Duo Drys fromTarget. Theyre cheap, dry fast, pack small and are easy to rinse/dry when theyget salty. Lay aside cleansocks/underwear/shirt/jeans for the flight home, then wear/recycle therest. Sometimes I run, so I also throwin a couple pair of shorts and socks.
I wear quick-starts or boat shoes on the way down/home and pack flipflops or Tevas.
Dont wear a swimsuits/wetsuits around town, inrestaurants. Its considered rude. Khaki shorts and golf shirts are considereddressing for dinner. If youre going outto dinner with locals/expats wear the khaki slacks. Thats what theyll probably have on.
My women mostly wear sundresses/shorts+blouses out todinner. Between dives they use swimsuitcover-ups for lunch/shopping.
edit: excuse the formatting/spacing - cut & paste from a document...