I've heard Hawaii is VERY casual, but could someone give me a little more clarification? Specifically for dining out. I'm pretty sure we will go to Sarrento's in Maui and we're staying at the Hilton Waikoloa on the Big Island, so we'll be hitting a couple of the restaurants in there also. Are shorts OK? T-shirts?
Thanks in advance!

Everyone wears shorts, but for Sarrento's or Hilton Waikoloa, I would recommend an Aloha shirt not a T-Shirt.

I'd stick with capri pants and nice shirt, not shorts in the evening -- short sleeved aloha or golf shirt for men, with jeans or slacks. Dress shorts might work as in Tommy Bahama etc... Very casual means you will never be required to wear a tie or jacket or that little black dress, if that helps. Have fun

We live on Kaua`i and travel throughout the islands. Have yet to hear of any restaurant which requires a tie, but most of the upscale ones require that men wear "collared shirts" -- and one or two in Honolulu require "dinner jacket" (we avoid the latter!)

Shorts at dinner are frowned upon, unless it's a golf resort and the man is wearing "dress shorts".

At dinner, ladies should always been in a dress (short and casual is fine) or long pants.

While I don't think you'll be turned away in shorts and a T-shirt, I would consider slacks and a collared shirt (maybe a nice Tommy Bahama silk aloha shirt) more appropriate for dinner for men. For women, a casual dress or sarong.

You won't be turned away from either of these restaurants in shorts or t- shirt but I agree with other posters: get an aloha shirt to complement your shorts and you'll be welcome everywhere (except maybe House Without a Key at Halekulani which still has a dress code).

Shorts and a t shirt are for beach side daytime. Slacks and a collar shirt are for night if you want respect and good service in higher end restaurants. Gals, same goes. There are spots you can go directly from the beach, but research. What kind of ambiance are you looking for and what do you want to see on the other guests?
The higher the price, the better the dress. International rules.

Wayne: We're staying at the Halekulani - what IS the dress code for House Without Keys"

I wasn't aware that House Without a Key had a dress code, only La Mer. When I go there in the evening, my husband wears slacks and an aloha shirt and I usually wear a dress. I'm sure during the day it's very casual and shorts would be fine for breakfast and lunch.