A rental car is essentially mandatory on Kauaʻi unless you plan to stay put at a single resort. The island is small but the main sights — Waimea Canyon, the north shore, the Nā Pali trailhead — are spread around it. The Kauaʻi Bus operates a public bus service linking the main towns, but routes are limited and frequencies low. Cycling is possible on the multi-use path along the east coast between Lihue and Kapaa.
Roads on Kauaʻi do not form a circuit — Highway 560 on the north shore ends at Keʻe Beach, and Highway 50 on the south shore ends at Polihale State Park. The interior is roadless. This means that to visit both coasts in a day you need to retrace your route.
Helicopters serve a practical transport function on Kauaʻi beyond tourism: some of the island's interior valleys and remote coastline is accessible no other way. Tour helicopters leave from Lihue Airport and offer a range of routes, with a landing tour to Mānawaiopuna Falls being the most popular premium option. Morning departures have the best visibility.