I'm goingto a wedding in Jamaica, what do I wear?

the guys are wearing linen pants and hawaiin shirts, the bride's maids are wearing long blue-green very thin dresses, no one's wearing shoes. should i do the long dress thing? short? casual? what color? should I do a bluish thing like the others to match, or will it be weird bc i'm not in the wedding? my bf is the best man, so Iwanna look nice too, but not go all out..