Upvote:2
Wikivoyage is a great usually-up to date reference for this, and in this case:
https://en.wikivoyage.org/wiki/Ukulhas - Nudism is prohibited. Swimming in bikinis is allowed only on the 1 main tourist beach and prosecuted in all other areas, a rule that is strictly monitored and enforced by the locals. Alcohol is banned by law but still can be arranged by some of the hotels, for highly inflated prices.
https://en.wikivoyage.org/wiki/Thoddoo - Thoddoo Island is surrounded by a wonderful beach. The locals are very friendly and very welcoming, but due to Muslim restrictions you can only swim at the designated tourist beach which sometimes is called the bikini beach. While outside the tourist beach it advisable to wear beach clothing rather than bikinis or swimming slips.
https://en.wikivoyage.org/wiki/Rasdhoo - Bikini beach. You can also snorkel and see Mantas, Stingrays and some sharks which will swim away once you try to get close to them.. However, its coral reef has started degrading due to touristic activity and perhaps will die off in several years. And yay, bikinis are allowed here, in opposite to all other beach areas on the island where it's strictly prohibited.
Conclusion: each island has realised tourism is valuable, designates a 'bikini beach', and that's the only place it's acceptable. As described, alcohol is feasible, but at a cost and not in public, and the locals will likely enforce any flouting of their clothing rules. Besides, it's best to try and fit in with the local customs to some extent.