The best cycling routes in Hilo Watershed Forest Reserve

Embark on a difficult touring bicycle journey up Mauna Kea, starting from Hilo. This route covers 46.9 miles (75.5 km) and challenges you with a significant 5612 feet (1711 metres) of elevation gain. You will cycle through five distinct climate zones, transitioning from lush rainforests to native dry forests, and eventually to a dramatic, almost lunar landscape. The ascent takes approximately 5 hours and 27 minutes, often placing you above the clouds. As you climb higher, you'll be rewarded with panoramic views, especially as you approach the astronomical observatories.

Planning for this difficult ascent requires careful consideration. Due to the massive altitude gain and reduced oxygen levels at higher elevations, bringing a support vehicle is strongly recommended for your safety. Be prepared for a roughly 7-kilometer section of gravel and sand after the Visitor Information Station; this part of the route is particularly challenging if you are on a road bike. Weather conditions can change drastically, so pack layers for warmth and wind protection, as temperatures can drop from warm at the start to freezing at higher elevations.

This epic journey is renowned as one of the world's most challenging bike climbs, offering a unique opportunity to experience Hawaii's diverse ecosystems. You will witness the landscape transform dramatically, from the vibrant greenery of Hilo to the stark, otherworldly terrain near the summit. The route's distinct climate zones and the presence of world-class astronomical observatories make it a truly remarkable and memorable cycling adventure.

The Rainbow Falls via Kaumana Caves loop offers a unique touring cycling experience through Hilo's lush Hawaiian landscapes, combining the visual splendor of an 80-foot waterfall with the raw geological wonder of ancient lava tubes. This moderate 7.8-mile (12.5 km) route, with 713 feet (217 metres) of elevation gain, can typically be completed in about 53 minutes, providing a refreshing ride through verdant scenery.

Parking is generally available near the start of the route in Hilo. Cyclists should be mindful of narrow or non-existent road shoulders on certain sections, like Waianuenue Avenue and Akolea Road. If you plan to explore the unlit Kaumana Caves, remember to bring a flashlight for the uneven lava rock floor.

What truly sets this route apart is the opportunity to witness the picturesque Rainbow Falls, often adorned with rainbows in the morning mist, and then delve into the fascinating Kaumana Caves, which offer a tangible glimpse into the Big Island's powerful volcanic history. It's a distinctive adventure for those looking to combine natural beauty with geological exploration on two wheels.

The Nana Stone Via Gilbert Carvalho Park loop offers a delightful and accessible touring cycling experience through Hilo's tropical landscape. This easy route, spanning 3.4 miles (5.4 km) with a gentle 298 feet (91 metres) of elevation gain, is mostly paved, making it a smooth ride for all. You'll cycle past lush Hawaiian flora and potentially catch glimpses of the Pacific Ocean, with the historic Naha Stone serving as a notable landmark along the way. It's an ideal choice for a quick, scenic spin, taking only about 22 minutes to complete.

Planning your ride on this family-friendly cycling route is simple, as it's designed for ease and accessibility. There are no complex permits or specific seasonal closures to worry about, making it a flexible option for visitors. Given its short duration and minimal difficulty, you can comfortably fit this loop into your schedule at any time of day, though a clear morning or late afternoon might offer the most pleasant conditions.

What truly sets this route apart is its blend of cultural significance and natural beauty, all within an approachable package. The Naha Stone itself holds deep historical importance, adding a layer of intrigue to your ride. As one of Hilo's many cycling routes, it stands out for its low elevation gain and short distance, making it particularly appealing for beginners or those looking for a relaxed exploration of the area without a strenuous commitment.