Last updated October 2026
The Wairau River is Marlborough’s largest river and a defining feature of the region, stretching approximately 170 km from its source in the Spenser Mountains to the sea at the Wairau Bar on Cloudy Bay.
This braided river flows east across the Wairau Plain, shaping the landscape, supporting the local wine industry and providing extensive recreational opportunities including fishing, jet boating, kayaking, swimming and rowing. Its Māori name is often translated as “many waters,” reflecting the multiple shifting channels that characterise its middle and lower reaches.
The river and its tributaries drain a large catchment and play a central role in flood management, irrigation and the ecology of inland Marlborough.
Practical Information
- Length
- Approximately 170 km
- Source
- Spenser Mountains, over 2,000 m
- Mouth
- Wairau Bar, Cloudy Bay
- River type
- Braided river, multiple channels across broad shingle bed in middle and lower reaches
- Major tributaries
- Branch River, Waihopai River, Omaka River, Opaoa River system
- Region
- Marlborough, drains the Wairau valley and plain
- Recreation
- Trout and salmon fishing, jet boating, kayaking, rowing, swimming, surfcasting at the mouth
- Fish species
- Brown trout, rainbow trout, sea-run brown trout, salmon, kahawai (at mouth)
- Fishing licence
- Required, Fish & Game Nelson/Marlborough region
- Closest town
- Blenheim, lower river runs north of the city
About the Wairau River
The Wairau rises in the Spenser Mountains and runs east through the upper Wairau valley, gathering tributaries including the Branch and Waihopai before reaching the wide Wairau Plain. Through much of its middle and lower course the river is classically braided, with multiple channels weaving across a broad shingle bed that shifts during floods.
Downstream of Blenheim the river passes Spring Creek and enters the sea at the Wairau Bar, a long shingle spit of significant historical and cultural importance. The bar is one of New Zealand’s earliest known Māori settlement sites, occupied from around the late 13th century.
The Wairau Plain, built by the river over millennia, supports Marlborough’s renowned Sauvignon Blanc vineyards. The river’s groundwater system supplies much of the region’s irrigation and municipal water. Marlborough District Council maintains an extensive flood control and river management programme to protect Blenheim and surrounding farmland.
Fishing the Wairau
The Wairau is one of the major trout rivers in the upper South Island. Resident brown and rainbow trout inhabit the upper and middle reaches, while sea-run brown trout are found lower down and salmon run seasonally.
At the mouth, surfcasters target kahawai. The river is large and braided, with conditions that can change rapidly after rain. A Nelson/Marlborough Fish & Game licence is required, and anglers should consult the regional access guide and regulations.
Full fishing guide: Wairau River Fishing Blenheim: Brown Trout, Sea-Run and Salmon
Tributaries and Connected Waterways
The Wairau system includes several notable tributaries. The Branch and Waihopai Rivers are important upper-valley contributors. The Omaka and Fairhall Rivers flow north across the plain, with the Omaka joining the Opaoa near Jacksons Road south of Blenheim.
The Opaoa River is a meandering lowland waterway that passes central Blenheim before joining the Wairau. The engineered Wairau Diversion helps manage flood flows in the lower reaches. This network provides varied recreation, from easy paddling on the slower Opaoa and Omaka to fishing and jet boating on the main braided stem.
Where to Access the River
Popular access points near Blenheim include the State Highway 1 bridge north of town, the Spring Creek area, the Wairau Rowing Club beach and the Ferry Bridge / Wairau Diversion area. Further upstream, Fish & Game publishes detailed access maps. Much of the river flows through farmland, so visitors must use designated access points and respect private property.
Safety on the River
The Wairau is a large braided river where levels can rise quickly after rain in the headwaters, even when conditions are fine on the plain. Side-channel crossings require caution as depths and flows can be deceptive.
The river mouth is used by jet boats and can have challenging surf, so swimming there demands extra care. Always check weather and flow forecasts before heading out.
Like Blenheim’s outdoors?
Explore Blenheim Weekly has a walk or park idea every week, plus local news and weekend picks. Free every Thursday.
Free. One email a week. Unsubscribe any time.
Frequently Asked Questions
How long is the Wairau River?
Approximately 170 km, making it Marlborough’s largest river.
Where does the Wairau River start and end?
It rises in the Spenser Mountains and flows east to enter the sea at the Wairau Bar on Cloudy Bay.
Is the Wairau a braided river?
Yes — through its middle and lower reaches the river is classically braided, with multiple channels across a wide shingle bed.
Can you fish in the Wairau River?
Yes. It is a major trout fishery with brown and rainbow trout, sea-run browns and seasonal salmon. A Fish & Game licence is required.
Can you swim in the Wairau River?
Yes in suitable spots, but conditions change quickly. Use known access points, watch river levels and avoid swimming during floods.
What does Wairau mean?
The name is often translated from Māori as “many waters,” referring to the river’s braided character.
What towns are on the Wairau River?
Blenheim lies near the lower river, with Spring Creek and Renwick also close by. The Wairau Bar is at the mouth.
Is the Wairau Bar historically significant?
Yes. It is one of New Zealand’s earliest known Māori settlement sites, dating back to the late 13th century.
Spotted something incorrect on this page? Let us know.
Related links 3
- Marlborough District Council — Wairau FMU: official information on the river catchment, management and freshwater planning.
- Fish & Game — Wairau Catchment: regulations, access details and fishing information for the Wairau system.
- Marlborough District Council — Rivers Overview: details on flood control and river management along the Wairau.