Stewart Island Rakiura New Zealand

January to March is the most comfortable window because the sea is at its warmest and daylight is long. Even then, expect cool water (often 11°C-15°C) and plan for wind changes. If you want guided snorkeling or freediving in Paterson Inlet, summer also has the best chance of calmer surface conditions for small boats. Shoulder months (November, December, April) can be excellent if you bring thicker neoprene and keep a flexible schedule. From May to October, trips still run, but cold water and frequent fronts make snorkel comfort and visibility more variable.

For scuba, aim for late spring through early autumn (November to April). You get longer days, a wider range of charter options, and warmer surface intervals, which matters when water can sit around 9°C-15°C. January to March is generally the easiest period for boat access beyond Paterson Inlet. Winter diving is possible for well-equipped teams, and some divers like the cleaner water after storms settle, but expect colder water, fewer calm days, and more cancellations. Build at least one buffer day in your itinerary either way.

Most travelers route through Invercargill (IVC). From there you either fly to Stewart Island (SZS) on a short hop, or drive about 29 km to Bluff and take the ferry to Oban (Halfmoon Bay). Flights are fast but have tight baggage limits (often 15kg), so heavy dive gear is usually easier by ferry. The ferry ride is about an hour and can be rough in strong winds, so pack seasickness meds if you are prone. Both services can be delayed by weather, so avoid scheduling tight same-day connections.

There is no general 'marine park tag' to enter the water, but you must follow strict rules in the Ulva Island / Te Wharawhara Marine Reserve: no fishing, no taking, no feeding fish, and no disturbing the habitat. The marine reserve boundaries are not marked, so use charts or go with an operator. Separately, Stewart Island/Rakiura has a visitor levy collected via approved operators for most short-stay visitors, and international visitors to New Zealand may pay the national IVL when applying for an NZeTA or visa. If you are hiking, the Rakiura Track huts and campsites must be booked and paid in advance.

Plan as if you cannot rent scuba gear locally. Stewart Island businesses commonly confirm that there are no local outlets hiring full scuba kits, and charters expect visiting divers to be self-sufficient. For snorkeling and freediving, you have better options: guided operators in Paterson Inlet provide masks, fins, and thick wetsuits (often 6.5mm plus an extra hooded vest) so you can focus on the experience. If you are flying, check baggage limits carefully and consider sending heavier items by ferry. Bring spares you would normally rely on a dive shop to replace.

Water temperature is the limiter for most people. In the Paterson Inlet marine reserve, divers report winter and shoulder-season temps around 9°C-11°C, with late summer typically peaking closer to 14°C-15°C. For scuba, most visitors are happiest in a drysuit or a 7mm wetsuit with hood and gloves. For freediving and snorkeling, expect thick neoprene, boots, and gloves, plus a warm windproof layer for the boat ride back. Cold reduces breath-hold comfort, so shorten sessions and warm up early.

Kiwi spotting is one of Rakiura's signatures, and you can often do it without a paid tour. Start near Oban on beaches and quiet tracks after dusk, especially on darker nights from April to September when it gets dark earlier. Use a headlamp on red mode, stay quiet, and keep a respectful distance so birds can keep foraging. Avoid flash photography and do not block a bird's path back to cover. If you want higher odds with less guesswork, book a local kiwi walk and ask what beaches are active that week.

The Bluff to Oban ferry is short, but the Foveaux Strait has a reputation for chop and swell, especially when strong westerlies are running. On rough days, people who never get seasick elsewhere can still feel it. Take seasickness tablets before boarding, keep cameras and valuables in a dry bag, and pack a windproof layer for the deck. Weather can also cancel sailings, so do not plan same-day international flights after your crossing. If you are carrying delicate dive gear, protect regulators and computers in your carry-on rather than checked duffels.

The Rakiura Track is one of New Zealand's gentler Great Walks in terms of elevation, but it is still true backcountry travel. The core loop is 32 km over three days, with huts and campsites that must be booked year-round. Expect sections of deep mud after heavy rain, boardwalks, and limited mobile coverage once you leave Oban. Pack waterproof layers, gaiters, and a headlamp even in summer. If you are unsure about three full days, use a shuttle to Lee Bay for a shorter first day, or take a water taxi to sample a section out and back.

In a suspected dive injury (decompression sickness, lung overexpansion, or near-drowning), treat it as an emergency. Call 111 first for urgent medical help, then contact the Diver Emergency Service at 0800 4DES 111 for dive-medicine advice. Give high-flow oxygen if available, keep the diver warm, lay them flat if conscious, and avoid unnecessary exertion. Stewart Island has a small medical service, but serious cases may require evacuation to the mainland and referral to a hyperbaric unit. Because help is remote, conservative dive profiles, surface support, and oxygen on boats are strongly recommended.