Mauna Loa Bike Climb - PJAMM Cycling

Mauna Loa


The longest bike climb in the world.

Page Contributor(s): Ron Hawks, Las Vegas, Nevada, USA Ties Arts, Bussum, Netherlands

Explore this Climb

Featured Video

PJAMM Cycling LogoDark Sky logo



If you love climbing by bike and would like more detailed information on the world’s top bike climbs, join our PJAMM Cycling group and receive our Special Edition Climb Report.
  • Receive a monthly report.
  • Get detailed and entertaining information on the greatest bike climbs and climbing areas throughout the world.
  • Discover beautiful landscapes with drone video and professional photos of remote and exotic places.
  • Gain insider knowledge on where to stay and how to conquer some of the most difficult climbs.

Climb Summary

Mauna Loa - the longest bike climb in the world

US Top 10 Most Epic Bike Climb

Ride 62 miles up, up, up . . . .

Photo:  Saddle Road on right; Mauna Loa Access road lower right to center

Aerial photo shows the entire shield volcano at sunrise.

Rarely do we have the good fortune of exclaiming “This is the _________climb in the world.”  There is only one hardest (Mauna Kea), one highest (Uturuncu), one most deadly (Death Road), and one LONGEST (Mauna Loa) in the entire world.


What good fortune we have that the hardest AND longest roads in the world are on the same Island (Hawaii’s Big Island).  At 62.2 miles, Mauna Loa is a good distance in front of the world’s second longest climb, Alto de Letras in Colombia (52.1 miles).

Cycling Mauna Loa - photo of cyclists riding Alto de Letras

World’s #2 longest bike climb - Alto de Letras, Colombia.

Surprisingly, of the two routes to the top of Mauna Loa, the longest route is also the lower ranked, coming in at #7 US/#60 World, versus the shorter at 44.8 miles, #4 US/#28 World (MAP).

PJAMM May 2018 Great Hawaiian Adventure Blog and Trip Page.

When to Climb Mauna Loa

PJAMM Cycling has taken on Mauna Loa once in May, twice in June, and once in December (we had to call in for help on that one as we got caught in a snowstorm at the top).  The lowest rainfall months on the Big Island on the eastern side (Hilo) are May and June and the highest rainfall months are March, April, and November. Thus, we recommend cycling the Hilo side in May and June.  The lowest rainfall totals on the western side (Kona) are February and December.  We have no data for the top of the volcano and in our experience it is best to climb in May and June.  The temperature throughout the year consistently averages in the 70s at sea level, meaning it’ll always be warm in Waikoloa when you start, but often cold at the top (it was in the 30s and snowing in December 2013 when we rode to the top).

Climbing Mauna Loa by bike - Mauna Loa Observatory Road - roadway and telephone poles with lava field

The weather can change in an instant on the volcano.

How to Climb Mauna Loa by Bike

While this climb is not as “hard” as its neighbor Mauna Kea, it is by far the longest bike climb in the world -- 124 miles round trip.  Train very seriously for this climb. The climb begins in Waikoloa Hilton Village by riding east (and yes, uphill) on Waikoloa Beach Drive, across Queen Ka’ahumanu Highway (mile three) then on up Waikoloa Road. We rise to 11,000’ so it is best to altitude train if at all possible.  Our training has only consisted of cycling up 10,000’ to Haleakala in Maui, before flying to the Big Island to climb Mauna Loa in preparation for Mauna Kea.  Since studies suggest it takes three weeks to become fully acclimated, unless you’re planning on an extended vacation, you’ll probably just have to suck it up and go for it without much altitude preparation.

Climbing Mauna Loa by bike - Mauna Kea Park - flags and visitor center 

Mauna Kea Park -- mile 38.5.

Bicycle ride of Mauna Loa - Mauna Kea park vending machines and provisions.

The only spot on the climb where provisions can be had. 

 The first segment from start to the right turn onto Mauna Loa Observatory Road is 44.6 miles, 3.2% average grade and gains 7,318’ over that distance.

 Start of climb -- Hilton Waikoloa Village (elevation is two feet here).

Waikoloa Road to Hwy 190 (15 miles) + Hwy 190 to Old Saddle Road (5 miles)

Cimbing Mauna Loa Volcano by bike - cyclists on old saddle road with cinder cone in background

Climb Old Saddle Road for 11 miles (gain 3,095’/descend 191’).


Old Saddle Road.

Bike climb Mauna Loa - Cyclist on Hwy 200 - Saddle Road

14 miles on new Highway 200 (Saddle Road) at 1.5% average grade.

At the 44.8 mile mark, turn right onto Mauna Loa Access Road and climb the final stretch to the Mauna Loa Observatory -- 17.5 miles, 4,457' climb, 17' descent with a 5.2% average grade.  This stretch of road is desolate, with very little traffic.

Bicycling Mauna Loa Volcano - turn off sign to Observatory Road

 Mile 45.

Mauna Loa as seen from Saddle Road (bottom middle) and Observatory Road (other 3 photos)

Cycling Mauna Loa Volcano - roadway, lava field and roadway sign

Road ends at the observatory -- not a through road.

Cycling Mauna Loa Volcano - roadway, lava field and roadway sign

Beware of fast changing weather, colder temperatures at the top and the effects of altitude.

The moonscape of Mauna Loa Volcano.

Bicycle climb Mauna Loa Volcano - Bruce Hamilton and Stacy Topping cyclists at Mauna Loa Observatory with bikes

Stacy and Bruce at the finish -- Mauna Loa Observatory in the background.

The one lane Observatory Road has been resurfaced as of 2013 and is in much better condition than its former decrepit state.  Of all the climbs you will ever do, this one will give you the feeling of being on the moon more than any other.  The lava fields range from smooth lava to basalt-looking rock that stretch for thousands of acres.  There is little to no vegetation along this route -- it is all lava with not only no green, but also not a bit of vegetation anywhere to be seen for miles.

Cycling Mauna Loa Observatory Road in poor condition 2011   

 Roadway in 2011 before it was repaved - quite the adventure!


Bicycling longest road in the world - Mauna Loa Volcano - undulating roadway

Mauna Loa Observatory Road is all about rollers.

View of Mauna Loa shield volcano from distance

After travelling 45 miles and turning onto the final leg, we still have a ways to go.

17.5 miles, 4,457' climb, 17' descent with a 5.2% average grade.

Climbing by bike Mauna Loa Volcano - cyclist climbing steep section of Mauna Loa Observatory Road

Although the climb averages 5.2% for the final 17.5 miles . . .

There are plenty of steep pitches.

Some Trip Tips

In our experience, the weather is better earlier in the day than later.  The most epic part of the climb (other than it being the longest in the world) is the last 17 miles: riding over the volcano moonscape on a narrow road with no traffic, passing by surreal telephone poles in site of the mighty Mauna Kea to the north.  The descent over the 17 miles of Observatory Road is equally unique and exhilarating.  Thus, if you’re short on time or don’t feel like you’ve trained enough, leaving in the early morning and just doing the 17 miles is an attractive alternative to the full ride.

Mauna Loa Access Road - 8,500’ - 8 miles to finish.

Mauna Kea in background.

The roadway from Waikoloa to the Mauna Loa Access Road is busy, particularly the start to mile 17 (turn off to Old Saddle Road/Highway 200) and then from mile 27.7 (back on main Highway 200) to the turnoff to Mauna Loa Observatory Road.  The remainder of the trip is quite the opposite of the first part; in our three trips up Mauna Loa Observatory Road we have seen no more than five cars - TOTAL!  Beware that there are absolutely no provisions or water available for the last 54 miles of this climb.  

Mauna Loa as seen from Mauna Kea -

views are to the south from Mauna Kea.

Left photo is from the gravel; 3 other photos are from near the top of MK.

The road from Hilo to Mauna Loa Access Road is busy and the traffic travels at a highway clip.  However, there are deep rumble strips separating the wide bike lane from the roadway for much of Saddle Road, and while the traffic can be a bit unnerving, for a highway this is a medium risk route.  In my six trips up Mauna Loa and Mauna Kea, I have never experienced a close call.  

Mauna Kea as seen from Mauna Loa.

Views are north to Mauna Kea from Mauna Loa.

The weather will be nice in Waikoloa or Hilo any time of the year you start.  However, also beware that 11,400’ up the volcano, weather conditions can change dramatically.  In December 2013, we left Waikoloa in 75 degree weather only to run into snow near the top of the climb.

Video is taken on Mauna Loa - Mauna Kea is in the background.

A Bit About the Mauna Loa Observatory

Built in the 1950s, the Mauna Loa Observatory (MLO) has been “monitoring and collecting data relating to atmospheric change, and is known especially for the continuous monitoring of atmospheric carbon dioxide” since 1958 as part of the National Oceanic and Atmospheric Administration.  This observatory is the oldest continuous CO2 monitoring station in the world, and is the “world's primary benchmark site for measurement of the gas” (Wikipedia).  Because the conditions of “undisturbed air, remote location, and minimal influences of vegetation and human activity” the MLO is an ideal location for monitoring atmospheric factors that can cause climate change (Mauna Loa, Hawaii Observatory).

Mauna Kea left and Mauna Loa to right of photo.

Photo taken on Waikoloa Road - 55 miles from the volcanos.

Visiting Mauna Loa

The Mauna Loa volcano is part of Hawaii Volcanoes National Park.  More information about visiting and camping in the area can be found on the National Parks Service website.  Note that due to the May 2018 eruption of the Kīlauea volcano, areas of this National Park are still in recovery (read more about the park’s recovery process in this article from the National Parks Service).  Though it is an active shield volcano, Mauna Loa itself has not erupted since April 15, 1984.

Mauna Kea to the north, 10 miles up Observatory Road (seven miles from top; 8,000’).

That’s a wrap!!