Front country - easily accessible
Loop
Undulating, some big hills
Native bush
Lakeside
Open tussock/grasslands
Open ridges/tops
Farm Road / 4WD Track
Easy Single Track
Moderate Single Track
Technical Single Track
Untracked / Route only
Average Uphill Gradient: +13.3%
Average Downhill Gradient: -13.3%
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7:00
Slow
5:30
Moderate
4:00
Fast
A great run in a beautiful part of the country, this run has a mix of easy trail to no trail, mostly runnable, bush and tops and lakes.
From the Cobb Reservoir take the Sylvester Hut track to Sylvester Hut (5.5km and 1 hour). Wide runnable track, gaining 450m over 4km so take your time.
From Sylvester Hut take the track to Lake Sylvester, then on to Little Lake Sylvester and Iron Lake (3km past the hut). By the time you get to Iron Lake the track is fading out, but still easy to follow.
From Iron Lake, pick your way up to the top of Iron Hill following cairns to the summit. You could sidle around to the right a bit before the summit, although missing out on great views further up the Cobb Valley and bagging a peak. Lake Lockett can be viewed to the NW from Iron Hill.
Follow the ridgeline off Iron Hill to the NW (better than dropping off the ridge too soon as on the map) until it's easy to drop down to the outlet to Lake Lillie. Sidle around from Lake Lillie above the bush until above Diamond Lake, then drop down through the bush to the lake. Don't drop down too soon, to avoid coming out below the lake - if unsure follow the edge of the bush around to the top of Diamond Lake, then follow the shoreline.
This is the section of untracked route done (4km from Iron Lake to Diamond Lake). From Diamond Lake pick up a trapline that goes to Lake Lockett and all the way back to almost the end of the run. The trapline has been formed into a technical single track that is runnable in many parts and is marked with red tin lids and triangles, not the standard DOC orange triangles.
At Diamond Lake look out for the first marker on the true left 10-20m below the lake outlet. From here it is well marked and generally easy to follow.
Lake Lockett is another highlight, and well worth deviating the 200m or so from the trapline (at a small tarn) to visit. After returning to the small tarn, make sure you follow the markers to the left (not right back to Diamond Lake).
Continue to follow the trapline for approximately 3.5km where you will cross Diamond Stream onto the true right. After another 3km the trapline comes out at an old quarry where a 4WD track takes you down the last 1.5km to the Sylvester Hut carpark.
This trail includes the peak Iron Hill.
Seven stunning lakes. Iron Lake, Diamond Lake and Lake Lockett being particular highlights with great camping spots to tempt you back and explore further.
If you know of any public toilets near the trail start or on the route, please login and then let us know so we can update this section.
Space for 12+ cars and plenty more back towards the reservoir.
49 km
72 minutes
Unknown
No
Moderate.
As for any alpine trail, only attempt in good weather.
Sidling around from Iron Lake can be a bit tricky, easier to navigate by going up Iron Hill (bagging a peak in the process).
When approaching Diamond Lake, don't drop down through bush too soon as you will come out below the lake. If in doubt, follow bush around bringing you to the top of the lake.
From Diamond Lake route follows a trapline - red triangles / round tins are used not the standard DOC orange triangles. Look for the first marker 10-20m below the outlet to Diamond Lake on the true left. This trapline is maintained by a bunch of keen and generous volunteers who are happy for people to use at their own risk.
Very patchy.
Thermal leggings, Long-sleeved thermal top, Seam-sealed waterproof jacket, Gloves, Beanie/thermal headwear, Personal Locator Beacon (PLB), Whistle, First aid kit, Extra food for emergencies, Survival bag, Cellphone, Compass, Map, Crampons / microspikes (for winter conditions)
No shortage of water. Unlikely to be issues drinking from any of the lakes or streams.
It can snow every month of the year in the Cobb, so always be prepared and check the forecast. Iron Hill and surrounds will have snow in winter and Iron Lake can freeze over - it gets cold up there!
Roots Bar
Takaka, Golden Bay
https://www.rootsbar.co.nz/
Great food and drink. Often live music
Mussel Inn
Onekaka, Golden Bay
http://www.musselinn.co.nz
World famous - thanks to Lonely Planet. Sitting around the fire pit talking about trail running is hard to beat.
Trail Legend
Fastest Known Times (FKTs)
You and Diamond in the Rough
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Absolutely amazing route, thank you so much for sharing it! I want to go back and do it again but swimming in all the lakes, and also to go back to camp by one of the lakes.
There are cairns and a worn path onto iron hill, I followed the GPX down to Lake Lillie but the ridge to the north looked a bit easier to desend so might try that next time. I found some goat trails here and there between Lillie and the woods above Diamond, followed the GPX down but would probably go around next time. From Diamond the trap line was really clear to follow. So good to have so much time on the tops, with plenty of water.
January 5, 2024
Very much enjoyed this loop! I set out uncertain if it would be manageable at this time of year but with a good weather window figured I'd give it a shot. The dodgiest part was Iron hill where it is in shade and there were some slippery bits of snow but I could dodge those and made it up easily. The decent to Lake Lillie was more difficult than expected (not helped by me landing in some sharp bushes!). After that the bush bashing through to lake diamond seemed simple and the trapline was fairly easy to follow from there. Such a beautiful place to explore. Thanks for sharing about the trapline otherwise I never would have known this was possible!
June 13, 2023
Loved it! So much variety! A great half-day adventure that could alternatively be titled "Seven Lakes Loop" - that's the real theme here. Agreed with Britta - I want to go back with a tent. Also agreed the views from Iron Hill summit were epic. I was happy enough with the rock scramble, but if you do not have a head for heights, or if the rock is wet, I would urge you to skip it.
I picked up a couple of wasp stings on the way back, including about 50m from the carpark, so consider bringing antihistamine.
Thanks Steve for submitting this to the trail directory. I would never have known about the trapline.
March 19, 2022
Well worth it. Stunning all the way up to the summit of Iron hill (small detour, and scramble to the top) from which you have 360 views onto lake country all around. Not to be missed. See if you can spot the Dragon's Teeth in the distance! Easy to follow track.
The only tricky bit of the entire route is dropping down to Diamond Lake from Lake Lillie, after traversing around the ridge to the N of Lake Lillie. I could not find any evidence of even a goat track anywhere. So it's a bit of a bush bash through the forest. Just close your eyes and push through until you pop out onto the beach of the lake. Fortunately this is section is short, easiest done by following your gpx.
Both Diamond Lake and Lake Lockett have beautiful camping spots which will make you want to stay the night. The trap line from Lake Lockett is very well maked and it's impossible to get lost here. Lovely loop!
March 14, 2022
These overlap with this trail to some degree. You may wish to combine them but please note that to qualify for FKTs on these runs you should record a separate activity for each.