I have not been to Niyama, but can comment on Cocoa island. Great diving, great snorkling right from the rooms. The island is small and the beach is small. The thing to do there is sit on your dhoni deck and snorkel off of it all day. There is beach but it is nothing spectacular. We enjoyed our time there, thought te food was good, and it was very accessible from Male - a boat ride away - not short, but we arrived at midnight and were still met and transferred by private boat. We were there a few years ago so information not fresh, but we enjoyed our time there and if you like snorkling and diving it is superb. We stayed in the room that is one up from the basic - it was two level - living room downstairs with full bath, and bedroom upstairs with half bath ( toilet nd sink).