Dress CodeAruba is a casual place. You can even wear shorts to most restaurants except Chez Mathilde or Le Dôme Restaurant. Le Dôme's website states their dress code inside is semi-formal and on the terrace it is casual. For men, you can wear a sports jacket if you like. People will really notice you if you wear a tie. In general, the women dress up a bit more than the men. If you tend to get cold in air-conditioning, don't forget your sweater!
Basic rule - if it looks good, and feels comfortable wear it, but if you are going to a nice restaurant, you should stick to the "casual-chic" look. You certainly don't want Arubans looking at you and saying, "Geez, look at how those tourists are dressed with beach shorts, and sneakers or slippers in a fancy restaurant. "