Fly through the ocean with giant manta rays, which have wingspans of up to six metres. These gentle and friendly creatures live off the Kona Coast, and at night you can see them feeding on plankton illuminated by spotlights from several resorts. But an even better way to see them is with a night boat tour. Tour operators set up giant lights on the ocean floor and snorkellers are treated to a mesmerising display. Curious rays often swim within centimetres of their human visitors. Tours are held year round, but the number of rays will vary depending on plankton levels.