If sailing doesn't fulfil your need for speed, give these zippy jetski tours a go. There are three-hour jaunts to Modriki Island (where Cast Away was shot, $595) and the Cloud 9 platform ($595), plus 30-minute/one-hour ($250/400) guided tours that bucket along past islands and reefs. It's based on Castaway and Malolo islands; free boat transfers are available from most Mamanuca resorts.