Lau are the most remote islands in Fiji. They are located in the south-east of the country. There are many uninhabited islands and excellent beaches, but most of that beauty is inaccessible for tourists. Shore and seabed: sand, stones. 
The best time for a holiday in Fiji is a dry season from May to November. However, if you are seriously thinking about these remote islands, you are unlikely to be confused by some rains in the low season.