heli fishing nz

South Island Fishing Overview

The South Island of New Zealand is famous around the world as a fly fishing destination. Large fish can be sighted and cast to in gin clear rivers. The style of fishing generally employed is more akin to hunting than simply casting into the water. This style of fishing is very addictive but requires stealth, patience and casting accuracy. In this overview of fishing in the South Island we will cover many of the things that are going to be required for success in this challenging but rewarding fishery.

The average size of trout in New Zealand sits at around 24 inches long and weighs 4lbs. Because of the general clarity of the water and the size of these fish, they are able to be sighted before they are cast to. The South Island has many rivers throughout its length, most of these rivers do contain trout. These rivers are often short, as they rise in the Southern alps which are only a short distance from the sea. This means that rainfall in the headwaters affects the flows quickly and dramatically. On the Westcoast more than 250 inches of rain falls annually in many of the catchments. With the frequent flooding of the rivers, aquatic insect populations are low and this means less food for the Trout. So with unreliable amounts of food and territorial behavior of the large Brown Trout in particular means the population densities of the trout is low. The trout attain their large size due to a combination of factors including; clear water allowing fish to feed for longer periods, catch and release, high protein terrestrial insects during summer and a less fish ultimately means more food for less fish in the river. So how many trout are there? Well some rivers have populations of 1-2 fish per mile. In the main in most South Island rivers you are likely to encounter 10 fish per mile. In some of the more stable catchments that are fed by lakes, you may well encounter upwards of 200 fish per mile but the trade often becomes a reduction in fish size. So now you know this information, it is now fairly obvious why we hunt the fish rather than cast into the water randomly. It can be very frustrating spending hours casting into the most beautiful pool you have ever seen, only to find out there were no fish in it to begin with. So we stalk the fish. To do this we move slowly and try and spot and likely shapes or subtle movements in likely places in the rivers. Often this means we cover several miles of the river in a day. Spotting the Trout is notoriously difficult. NZ fishing guides have amazing eyesight and are worth booking for this fact alone! You could potentially be walking past fish which often means lots more walking to the next one. 


The most often used rod weights in the South Island are in the 5 to 6  weight range. Medium to fast actions are preferred. These rods are coupled with floating weight forward lines.

One of the most surprising elements to sight fishing in NZ, is how close we get to the fish before casting. The reason we like to be close is to fish a good drift to the fish. NZ often see a lot of fishermen during the season. They become very wary once they have been hooked and have long memories! In order to catch these educated fish we need the fly to be drifting past the fish in the most natural manor. The more fly line and leader we have on the water, the more risk there is of the currents contorting the fly line and introducing drag into the drift. Most of the presentations we make are from around 30 feet from the fish. To complicate this, we fish with a long leader. The minimum leader length sits at around 12 feet. Some rivers require a leader of 18 feet or more, particularly in summer low flows and in highly pressured waters. In the main a 14 to 16 foot leader will cover a lot of situations. So short casts with long leaders are the order of the day. To be consistently successful on the South Island, an angler needs hit a 3 foot wide target from a distance of 30 feet in a range of wind conditions with different sized flies 9 out of 10 times ( all while looking at the biggest trout you have ever fished to!). For the rest of us success is possible - just not as consistently. Hiring a guide to tweak your casting will pay dividends, not only here but for your fishing on the whole. 

Adding even more complexity to this is the fly. Sometimes we need to use very heavy tungsten Nymphs to get down to fish that will not lift in the water column to take a dry fly. We can change fly many times on a fish during the process of catching it. Often the fly is changed because of the depth required to get the fish to take. When a fish will not look at a presentation, it is very commonly because it is not drifting where or how the fish wants it to be. This is another reason a guide is invaluable. They can read your drift and see the fish respond to your offering and make the necessary changes to entice a positive take. No two fish are ever the same, one minute you could be fishing a heavy size 8 Stonefly with two tungsten beads and the next casting a size 18 dry fly to a rising fish on the edge of a swift run.

The South Island is a place where wet wading with merino wool or polypropylene tights are worn under quick drying shorts. We cover a long distance in a day and wearing uncomfortable, sweaty waders is not the best option. Early or late in the season waders are a definite advantage. At these times all fours seasons can be experienced in one day. A good jacket is a must! - even in summer. Summer day time temperatures range from around 68 deg F through to 80 deg F. Early and late season (October, April) The daytime high might be 65 deg F. Water temps can be cool all season and the thermal leggings will help with this. We don't spend much time in the water during the day, usually only on crossings and while fishing to a fish that requires a clear back-cast. Most of the time we are out of the water to avoid spooking fish. Another reason for leggings is to keep the voracious NZ Sandflies (like No See-Ums) from biting your legs, they can be irritating is some river systems. One last consideration regarding clothing is color. We can see the trout but they can also see you. The object is not provide a contrast to the rivers surrounds. Ideally not wearing bright block colored clothing and hats will improve your chances. Broken patterns in sombre greys and greens are ideal - So leave your white or red hat at home! 

Quality polarized sunglasses are an absolute must! Not only for New Zealands high UV index but for spotting trout. Generally if you cant see them in the South, you cant catch them!

We use very few fly patterns here in the South Island. Often to be successful the presentation is more important than the replication. It is more important that the approach and drift is correct than the fly used. In the main a well presented fly will get close inspection from a trout. With insect densities being so low the trout here are not often that fussy. Guides in NZ carry many flies, however most of the them look similar and are very drab in coloration. The guide will have many different sizes and weights of his patterns which is so often the difference between success and failure. 

A great fishing day is possible on any given day during the South Island fishing season. It is a matter of applying the right techniques in the right conditions that is most critical. So below is a description of the South Island fishing season to help decide the best time to make your trip.


This is when the main headwater and backcountry fishing season begins. Most upper sections have been closed for up to 5 months to allow trout to spawn. This is a great time to visit the Nelson region for Brown Trout. These fish are feeding well to put condition on post spawning and will move a long way to take large nymphs. These fish are often less wary as they have been left alone by fishermen over winter. A great time for your trophy Brown Trout!


Brown Trout are now feeding for longer periods of the day and more consistent dry fly fishing is taking place. Opening for most of the rest of the rivers that contain Rainbow Trout. Good time to pay a visit to The South Canterbury and Otago regions to fish newly open rivers. Nelson and North Canterbury Brown trout fisheries have still not received much pressure from anglers. 


The beginning of terrestrial fishing. Beetles are now on the wing and the trout are looking up. The larger rivers are starting to fish well as river levels begin to drop as the spring run off ends. Much warmer days and wet-wading begins to come into its own. Middle of the day Mayfly and Caddis hatches.


The busiest month on the South Island rivers. NZ holiday season lasts until the middle of the month. This is the coldest month in the US, so guides are out most days. This is Cicada time. Large Cicadas hatch and their chirps are deafening in most of the river valleys. A great time to see a large trout taking from the surface. Leaders are longer now and indicators are removed when nymphing. Very warm daytime temperatures.


Another warm month. The Cicada hatch continues. Some fish begin to get wary of large hopper patterns but will still take smaller dries. Most settled weather begins now. Guides are still busy with US clients. Good evening caddis hatches.


Beginning of  consistent mayfly and caddis hatches in both Nelson and Southland. Fishing pressure is starting to ease off on the rivers. The settled weather continues and Brown trout have now started to move upriver towards spawning areas.


Brown trout spawn runs have well and truly started. Most consistent Mayfly hatches of the year especially in Southland. Some large trout have moved into rivers from lakes. Rainbow Trout can now be caught behind spawning King salmon in East Coast headwaters on egg patterns. Very few fishers on the rivers. 



Brown Trout rivers in Nelson, Marlborough, Westcoast and North Canterbury have closed in the upper reaches for spawning. Rainbow Trout catchments in Otago and Central South Island are open until the end of the month. Migrations of fish from lakes is peaking during this month. Most fish taken subsurface on eggs or streamers but on warm days dry fly is still possible.  

June to September;

This is wintertime. All upper river sections have closed. There is still great fishing to be had in Mackenzie country hydro canals for giant Rainbow and Brown Trout as well as King Salmon. Fishing lake margins and around stream mouths with streamers and very productive. The lower reaches of the rivers also provide good sport for Sea run  Brown Trout. These can be large and take big streamers around the river mouth areas. A great time to visit the South as Skiing is world class as are the golf courses and mountain biking trails. These activities can be added to your fishing trip to make a nice relaxing getaway. 

So in summary, the South Island is a world class fishing destination. Catching large trout in clear water with a picture postcard backdrop is possible. So if you can get your head around stalking trout, short casts with long leaders and walking a mile or two a day, then let click contact us and we can help you arrange a trip to remember!

south island fishing