Yes, even at the nicest restaurants, shorts and t-shirts are fine. Sandles optional.
But, it is fun to wear a cute little sundress out at night too.
(Unless of course you are like me.... I still after 3 years MUST pack at least 2 outfits per day, plus something for dinner. I already have closets full down there, but it's one of those obsessions that I can't seem to shake. AND, how many times have I actually worn a sundress to dinner, maybe twice in 3 years.)
But, I give great advice on packing!!!!!!!
Have a great trip!
Cheerz!