Safety · Destination Guide
Stewart Island Rakiura New Zealand
Cold-water kelp forests, a no-take marine reserve, and Great Walk wilderness in New Zealand's Deep South
Updated Feb 13, 2026 • 21 sources
Safety And Conservation
Stewart Island diving and adventuring is remote, cold-water, and weather-led. The safest trips assume delays, carry redundant safety gear, and follow conservation rules to the letter, especially in the Ulva Island / Te Wharawhara Marine Reserve.
Top Risks
- Primary risk: Foveaux Strait sea state and cancellations
- Secondary risk: Cold water and rapid chilling
- Emergency contact: Emergency Services (111)
- Safety overview: Stewart Island diving and adventuring is remote, coldwater, and weatherled.
Dive safety
- Cold-water protocols: Dress for 8°C-15°C water and plan short, conservative profiles. Hypothermia risk is real even on sunny days.
- Weather and sea state: Paterson Inlet is the sheltered plan; Foveaux Strait and the outer coast can be rough with surge and current.
- Surface support: Boat dives should carry oxygen when possible, plus radio/VHF and an agreed float plan.
- Navigation and pickups: Carry an SMB, whistle, and light. In kelp, maintain buddy contact and avoid pushing into thick canopy in poor visibility.
- Protection rules: Marine reserve boundaries are not marked. Treat "no take" as absolute and avoid any contact with sensitive habitat.
Stewart Island has a small local medical service in Oban for primary and urgent care, with limited resources compared with the mainland. For serious injuries and dive emergencies, evacuation to the South Island may be required.
- Emergency number: Call 111 in New Zealand for police, fire, or ambulance.
- Dive medicine support: Call the Diver Emergency Service (DES) at 0800 4DES 111 for specialist advice.
- Recompression: Hyperbaric treatment may involve transfer to a mainland hyperbaric unit (often coordinated through emergency services and DES).
Because help is remote, bring a well-stocked first-aid kit for boating and tramping, and do not dive or hike beyond your ability to self-manage for a longer period than usual.
Snorkel and freedive safety
Foveaux Strait sea state and cancellations
The ferry crossing is short but can be rough, and both ferries and small-plane flights can be delayed or canceled by wind, low cloud, and sea state. Windy fronts (30.0 kph+ on exposed days) are common in winter. Build buffer time and carry seasickness medication if needed.
Cold water and rapid chilling
Most in-water sessions are limited by temperature, not air. Use thick neoprene or a drysuit, shorten sessions, and warm up early. Cold can also reduce breath-hold performance and increase risk.
Limited scuba support on-island
Do not assume you can rent a full scuba kit, get specialty parts, or find last-minute fills. Bring spares and confirm logistics before you leave the mainland.
Sandflies in calm, damp conditions
Biting sandflies can be intense around sheltered bays, especially when there is little wind. Pack repellent and cover up at dusk.
Wildlife and protected areas
Stewart Island's underwater highlights exist because the ecosystem is still functioning. Protect it.
- Ulva Island / Te Wharawhara Marine Reserve: No fishing, no taking, no feeding fish, and no disturbing marine life or habitat. Discharging pollutants or introducing organisms is illegal. Boundaries are not marked on the water, so use charts or go with an operator.
- Wildlife etiquette: Give seals, penguins, and seabirds space. Do not chase wildlife for photos.
- Biosecurity: Ulva Island is managed as a sanctuary. Check bags and footwear, clean gear, and avoid transporting seeds, soil, or food scraps.
- Leave no trace: On tracks and beaches, pack out all litter and keep to formed paths where possible.
Do Not Do This
Avoid entering when foveaux strait sea state and cancellations. Confirm local briefings before committing.
Emergency contacts
| Contact | Role | Phone | Availability |
|---|---|---|---|
| Emergency Services | Police, Fire, Ambulance | 111 | 24/7 |
| Diver Emergency Service (DES) | Dive medicine hotline | 0800 4 337 111 | 24/7 |
| Stewart Island Medical Service | Local clinic | +64 3 219 1098 | Clinic daily (limited hours); on-call support available |
| Coastguard New Zealand | Marine rescue | 111 (urgent) or VHF Channel 16; *500 for non-urgent from a mobile | 24/7 via emergency channels |
| Rescue Coordination Centre New Zealand (RCCNZ) | Search and rescue coordination | 0508 472 269 | 24/7 |