While most kayaking or stand-up paddleboard adventures in Hawaii take place out at sea, there are a few opportunities to enjoy these activities without the salt water, waves or sharks you'll find in the Pacific Ocean. The Wailua River is Kauai's third longest river, and it is the only river in the entire state of Hawai‘i that is large enough to support boats and tours. While you are not allowed to currently go up the North Fork due to flood damage, the South Fork offers a route to the beautiful Fern Grotto, a state park that is only accessible by watercraft. Unfortunately, due to the flood damage, this means no access to the famous Secret (Uluwehi) Falls. At the time of this write-up there are no kayaks allowed past the Hawaiian Village, which sits just before the split in the river between the North Fork and South Fork. One way to still access Fern Grotto is to rent stand-up paddleboards, which enjoy a legal loophole that allows their use past the Hawaiian Village. If you would like to avoid paddling back down river against very strong winds, request kayak paddles from the rental shop. This gives you much more power and ease behind each stroke and keeps your standing body from acting like a giant sail, making the journey back significantly easier. Note, however, that even moderate winds can still pose a challenge while using this method. A regular stand-up paddleboard position would be very difficult in high winds.
Overall the trip is relatively easy, especially while paddling up river with the wind at your back. The Fern Grotto is about 4 miles round trip, but it will take much longer on the return in terms of time. Launch your kayaks or stand-up paddleboards from the marina boat launch just a short ways up river in the town of Kapa‘a. There are many places to rent stand-up paddleboards on your own, and you will receive car racks to get your craft to the launch. There are also guided kayak tours available that will do all the craft transportation for you, but you will not be allowed to see the Fern Grotto. Once the restrictions are lifted, make sure to hit up Secret Falls, really the main attraction, by taking the North Fork when it is open.