Last updated October 2026
The Waikato River below Karāpiro Dam is, according to Fish & Game, probably the single most popular fishing spot in the Auckland/Waikato region. Rainbow and brown trout hold along the edges of the backwater at the base of the dam, feeding on small fish and caddis, and the river is open all year to fly, spinner and bait.
Most anglers fish from the western bank, reached by a track beside the transformer station; the eastern bank is steeper and quieter. The river can rise quickly when generation changes, so keep an eye on the water the whole time you fish.
At a Glance
- Location
- Base of Karāpiro Dam on the Waikato River, about 30 km upstream of Hamilton
- Water
- Waikato River (fresh)
- Main species
- Rainbow trout all year; brown trout mainly from late autumn to December
- Best time
- Early morning and the first hour or so after dusk
- Methods
- Fly, spinner and bait (smelt or worm) all allowed
- Access
- On foot: track beside the transformer station (western bank) or the steep slope off the powerhouse road (eastern bank)
- Season
- Open all year
- Licence
- Fish & Game licence required
- Rules
- Fish & Game Auckland/Waikato Anglers Notice
- Flows
- Mercury river flows line, 0800 820 082
No tides. Flows below the dam change with power generation and the river can rise quickly; clear water at lower flows usually fishes best.
About Waikato River below Karāpiro Dam
Karāpiro is the last of the hydro stations on the Waikato River, 188 km downstream of Lake Taupō. The concrete arch dam, 335 m long and 58 m high, was started in 1940, delayed by the Second World War and finished in 1947.
A refurbishment completed in September 2025 lifted the station’s output. Below the dam the river returns to its old course about 30 km upstream of Hamilton.
The name comes from 1830, after the battle of Taumatawīwī, when Ngāti Hauā and Ngāti Korokī fought Ngāti Maru. Te Waharoa cremated his fallen warriors on a column of rocks near the Hauoira Stream outlet.
The rocks became tapu and the place was named Karāpiro, from karā (rocks) and piro (a putrid smell). The lake drowned the rocks in 1947, and a memorial now stands at Karāpiro Domain.
Below the dam the river is big and deep. Trout hold right on the edges to ambush migrating baitfish, mostly within about 10 m of the rod tip, so you rarely need a long cast.
Rainbows are plentiful from Hamilton up to the dam and stay in the river all year. Browns average about 1.5 kg, and fish over 2.5 kg are common; they drop down from the Waipā headwaters after spawning in April and May and stay in the Waikato until about December.
Downstream toward Cambridge the river can only be reached by boat. Anglers there moor and walk the big shingle beds at low flows, where trout feed on caddis, while further down there are backwaters, boulder banks and submerged trees. Near Cambridge, the mouth of the Karāpiro Stream is a popular spot, best at low flows, with tracks along both banks.
How to Fish Below Karāpiro Dam
Where to fish
On the western side, a track next to the transformer station leads straight down to a large backwater at the base of the dam. About halfway down, another track branches left to a rocky point directly opposite the station.
The eastern side is much harder to reach and gets less fishing pressure: walk down the steep slope about halfway along the road to the powerhouse. Keep out of any marked safety zone around the dam and its outlets.
When to fish
Early morning and the first hour or so after dusk are the most productive times, when trout move in close to the bank to feed on small fish and caddisflies.
Across the river, winter often fishes best, because the water clears once the summer algae die back. Keep a low profile and stay back from the edge in daylight; after dark you can fish closer.
Flies, lures and bait
- Spinning: T-tail or paddle-tail soft baits are the most effective, along with a black Toby, copper Zed, red Veltic, rainbow Rapala and brown or black Tokoroa Chickens. Use bigger, darker lures when the river is high. Cast across or slightly upstream and retrieve slowly, with the odd jerk.
- Fly: wet flies outfish nymphs and dries here. Use an intermediate or sinking line by day and a floating line after dark. An olive-green or black rabbit fly in sizes 4 to 6 is the standard; a big black rabbit is best at night or in coloured water.
- After dark: spinning with a fly and a split shot is far more effective than a lure.
- Bait: a smelt or worm on a size 6 hook under a small ball sinker, popular with young anglers. Smelt can be caught with a baitcatcher and bread; bait fish must come from the water you are fishing.
Reading the flow
Flows below the dam change with power demand, and the river can rise rapidly. If the water starts creeping up the bank, move back to higher ground straight away. Mercury’s flows line, 0800 820 082, gives the current flow below Lake Karāpiro.
Rules and Safety
- The river below Karāpiro Dam comes under Fish & Game Auckland/Waikato’s rules for all other rivers and streams: open all year, with fly, spinner and bait allowed. The 2026/27 Anglers Notice took effect on 1 October 2026.
- You need a Fish & Game licence and must carry it. One rod only. Felt-soled waders are banned. Bait fish must come from the water being fished, and never move water between waterways.
- The river can rise quickly with power generation. The banks are steep, and the water is deep and fast with hidden rocks. It is not patrolled.
- Between the dam and Cambridge there are large whirlpools and many submerged trees along the edges. Wear a lifejacket in a boat.
- The steep banks and changing flows make this a poor spot for small children.
Getting There and Facilities
- Road: the dam is a short drive from Cambridge, and a single-lane road runs across its crest.
- Parking and toilets: there are no signposted angler facilities at the base of the dam. The nearest council reserves are Mighty River Domain and Waipuke Park on Lake Karāpiro, above the dam.
- Boats: the reach from the dam down to Cambridge is boat access only and suits experienced boaties.
- Cycling: the Te Awa River Ride runs 15.2 km between Cambridge and Lake Karāpiro.
Tackle and Bait Nearby
- Hunting & Fishing Cambridge, 2 Oliver Street, Cambridge: trout tackle, lures and Fish & Game licences.
- Hunting & Fishing Waikato, 674a Te Rapa Road, Hamilton: tackle and Fish & Game licences.
Where to Learn More
Fish & Game: trout in the Waikato River: access, methods and seasons along the river, including Karāpiro.
Fish & Game Auckland/Waikato regulations 2026/27: current seasons, methods, limits and licence rules.
Mercury: lake levels and river flows: Lake Karāpiro levels and the river flows phone line.
Waikato River below Karāpiro Dam: Common Questions
Where do you fish below Karāpiro Dam?
From the western bank, using the track next to the transformer station down to the backwater at the base of the dam, or from the quieter eastern bank off the powerhouse road.
What trout are in the Waikato River at Karāpiro?
Rainbow trout all year, and brown trout that drop down from the Waipā after spawning and stay until about December.
Is the river below Karāpiro Dam open all year?
Yes. It is open all year under the Auckland/Waikato rules for rivers and streams.
Can I use bait below the dam?
Yes. Fly, spinner and bait are all allowed. Smelt or worms on a small hook are popular.
When is the best time to fish?
Early morning and the first hour after dusk, when trout move in close to the bank. Winter is often best because the water is clearer.
Do I need a licence?
Yes. You need a Fish & Game licence, which covers New Zealand except the Taupō fishery.
Is it safe?
Take care. The river can rise quickly with power generation, the banks are steep, and the water is deep and fast.
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