Last updated October 2026
Port Underwood (Te Whanganui) is a narrow, south-facing harbour at the south-eastern edge of the Marlborough Sounds, opening just north-west of Cloudy Bay. It is about 9 km long, with steep bush and forest down to the water.
Summer schools of kahawai work the surface, blue cod live on the outer reefs, and rig, tarakihi, moki and butterfish are also caught. Oyster Bay, with a wharf and ramp, is the main access for trailer boats, and Port Underwood Road links the harbour with both Rarangi and Picton.
At a Glance
- Location
- South-eastern edge of the Marlborough Sounds, between Cloudy Bay and the Tory Channel entrance
- Type
- Enclosed harbour, about 9.3 km long and 3.5 km wide, with many small bays
- Depth and bottom
- Channels 10 to 20 m; mostly sand or mud, dropping quickly to 10 to 15 m
- Main species
- Kahawai in summer, blue cod on the outer reefs, rig, tarakihi, moki and butterfish
- Launching
- Oyster Bay wharf and ramp (main access, limited parking); beach launching at Tom Canes Bay for small craft
- Road
- Port Underwood Road from Rarangi or from Picton via Waikawa; winding, with unsealed sections
- Tide port
- Oyster Bay (LINZ secondary port, from Wellington)
- Rules
- MPI Challenger (Challenger East blue cod rules); scallops closed; no set nets
- Licence
- None needed for sea fishing
- Low about 5:15 am
- High about 11:29 am
- Low about 6:00 pm
- High about 11:51 pm
Best times today: around 5:15 am, 11:29 am, 6:00 pm and 11:51 pm (2 hours either side of each tide change).
Moving water around the tide changes usually fishes best. Full 7-day Blenheim tides ›
Predictions only; actual tides vary with weather.
What You'll Find Here
Port Underwood faces south, with a narrow entrance near the northern end of Cloudy Bay. Steep, forested hills rise straight from the shore, and a tongue of land splits the harbour into two arms. Channel depths run from 10 to 20 m, and most of the seabed is sand or mud that drops away quickly to 10 to 15 m.
The harbour has a long European history. Whaling stations were set up here in the 1820s and 1830s, including John Guard’s at Kakapo Bay, and by 1840 around 150 Europeans lived around the harbour.
At Ngākuta Bay the Ironside Cairn marks the Reverend Samuel Ironside’s Methodist mission of 1840. Remains of the coal hulk Blackball, which drifted and grounded on Blackball Point after 1923, still lie in the shallows.
Today mussel farms line several bays, and a commercial wharf at Hakahaka Bay serves the farms. Ocean Bay, Oyster Bay and Hakahaka Bay are well-known anchorages, and several other bays are used as overnight stops.
How to Fish Port Underwood
From a boat
Most fishing here is done from small boats launched at Oyster Bay or Tom Canes Bay. Blue cod are found on the reefs toward the outer harbour rather than over the sand and mud of the inner bays. In summer, watch for birds working over schools of kahawai on the surface.
From the shore
The bays drop quickly to 10 to 15 m, so a cast from the rocks or beaches reaches fair depth. Keep well clear of the Oyster Bay ramp and wharf while boats are launching, and of mussel farm lines.
What to catch
- Kahawai: summer schools that break the surface, often shown by birds.
- Blue cod: on the outer reefs. Check the rules first (see below).
- Rig, tarakihi, moki and butterfish: also present in the harbour.
- Snapper: may be scarce here. Ask at a Blenheim or Picton tackle shop for what has been caught recently.
Getting There and Facilities
- From Blenheim: drive to Rarangi via Tuamarina, then take Port Underwood Road over the hill past Whites Bay and Robin Hood Bay.
- From Picton: Port Underwood Road runs past Waikawa and Whatamango Bay, then climbs steeply before dropping into Oyster Bay. DOC describes the road as historic, winding and unsealed, so allow plenty of time and drive it slowly with a trailer.
- Road works: the road was damaged in storms. Marlborough District Council reported repairs completed in early 2026, with crews back on site under stop/go traffic control. Check the council’s road alerts before you go.
- Oyster Bay: the main trailer boat access, with a wharf, ramp and limited parking. Boating New Zealand’s August 2025 guide to the harbour also lists diesel at Oyster Bay. Do not count on buying fuel there without checking first.
- Tom Canes Bay: near the harbour entrance, a sheltered beach where smaller craft can launch.
- Tumbledown Bay Road: narrow gravel, slow going and not suited to launching trailer boats.
- Supplies: there are no shops in the harbour. Buy bait, ice and food in Blenheim or Picton.
Rules and Safety
- Area: Port Underwood is in MPI’s Challenger area. MPI’s Marlborough Sounds Area for blue cod ends at the Tory Channel entrance, north of Port Underwood, so the Challenger East blue cod rules apply here rather than the Sounds closed season. Check the map in the NZ Fishing Rules app before you keep blue cod, and remember that the Sounds blue cod season is closed from 1 September to 10 January if you head north.
- Scallops: the Port Underwood scallop fishery has been closed since 15 July 2018, until further notice.
- Set nets: set netting is banned in Port Underwood, apart from a limited summer exemption with strict conditions. Read MPI’s Challenger rules before setting any net.
- Cook Strait cable zone: the cable protection zone lies north of the harbour, marked at Walker Rock. It is closed to fishing at all times.
- No licence: you do not need a licence for sea fishing, but Challenger size and daily limits apply.
- Weather: a strong southerly blows straight into the harbour, and boaties often leave early when one is building. Check the MetService marine forecast for Cook Strait before you launch, and wear a lifejacket in small boats.
From locals
Are there any shops at Port Underwood for bait and food?
Does anyone fly fish for kahawai from the shore here, or is it mostly boats?
No answers yet. If you know, a local would love to hear it.
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Common Questions
Where is Port Underwood?
At the south-eastern edge of the Marlborough Sounds, with its entrance just north-west of Cloudy Bay. Port Underwood Road reaches it from Rarangi or from Picton.
What can you catch at Port Underwood?
Kahawai in summer, blue cod on the outer reefs, and rig, tarakihi, moki and butterfish. Snapper may be scarce.
Does the Marlborough Sounds blue cod closure apply in Port Underwood?
MPI’s Marlborough Sounds Area ends at the Tory Channel entrance, north of Port Underwood, so the Challenger East blue cod rules apply. Check the map in the NZ Fishing Rules app before you keep any.
Can I take scallops in Port Underwood?
No. The Port Underwood scallop fishery has been closed since 15 July 2018.
Where can I launch a boat?
Oyster Bay has a wharf and ramp with limited parking. Smaller craft can launch from the beach at Tom Canes Bay near the entrance.
Is there fuel at Port Underwood?
Boating New Zealand’s August 2025 guide lists diesel at Oyster Bay. Check before you rely on it, and fill up in Blenheim or Picton.
Is the road to Port Underwood sealed?
Not all of it. Port Underwood Road is winding, with unsealed sections, so allow plenty of time, especially with a trailer.
Do I need a licence?
No. Sea fishing in New Zealand needs no licence, but MPI’s Challenger limits apply.
Spotted something incorrect on this page? Let us know.
Related links 2
- MPI Challenger fishing rules: blue cod rules, the scallop closure, the set net ban and the Sounds closed season.
- MPI: Marlborough Sounds blue cod closed season: the extended closed season and the areas closed to fishing at all times.
Sources and data notes 1
- Tides today: Tide predictions: LINZ (CC BY 3.0 NZ), adjusted from Wellington using LINZ secondary port offsets.