Maui kayaking is best along the southwest coast.

Maui Kayaking Locations
Kapalua Bay - good for beginners (can rent kayaks at Kapalua beach)
Black Rock (N Ka'anapali Beach) - good for beginners
Ulua, Mokapu, Holoa Point, Makena Landing - good for beginners
Guided tours also available (see sea turtles, dolphins and whales!)