Where is the best place to stay in Fiji for snorkeling and kayaking?
Stayed in Barefoot Lodge resort. "Rustic" setting, but snorkeling was amazing, especially when you kayak around the corner, across Mantaray Island Resort that Jan T mentioned. We also stayed at Blue Lagoon Beach Resort, which didn't have as great snorkeling, but beach was beautiful and nicer lodging options.
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Mantaray Island Resort is the place.
If you want to see more Fiji buy the Bula pass that give you the option to move around.