Kauai is unique among the islands of Hawaii for having the only navigable rivers in the state. You can rent one- and two-person kayaks for self-guided touring and explore the north fork of the Wailua River, or travel up the Hanalei River through a Federal Wetlands bird refuge. For the more adventurous, there are guided ocean kayak trips. During the summer months, this is a spectacular way to view the Na Pali coastline. In winter, it's more comfortable to explore Kauai's southern shores.