Will my AT&T plan for my iphone work in Hawaii as it does in California?

I'm going on a short trip to Hawaii and I was wondering if there would be roaming or long distance fees when I'm in Hawaii? Or will the plan / cell usage be the same as it is when I'm at home (in California)?

Hawaii is still US soil so you will most likely get reception still but probably not the best internet like 4G LTE.

Call ATT customer service, talk to a human, and ask.

Yup, got it myself, my plan werk fine in Cali, yours gonna werk hea fine too, ok? Now, not fully cover hea Hawaii, like it mosly is in Cali, gotta few place that not get good service, but mosly it good, on Oahu, onna otha island, well not so much, so if you come Oahu, no problem, if going to Molokai, well, less coverage, ok? Hope this help, peace an aloha to you!