Fill your bag with light cotton clothes since it is hot from October to May. Think also about a hat, sunglasses, flip-flops, and a raincoat which may prove useful in case of big summer rain. Do not forget plastic shoes if you want to avoid sea-urchin pricks or other possible flesh wounds with corals or shells (depending on where you swim).
From June to September, bring trousers and sweatshirts/jumpers for cool evenings.
Do NOT forget mosquito repellents!
Note: Nudism and topless are not welcome on Mauritius beaches