THE TAKE IS BRUTAL and resolute – like an unexpected punch in the stomach. I’ve sent an obstinate cast into the howling onshore winds, and even though I haven’t quite stretched the leader, I’ve managed to reach the drastic and alluring drop off that runs along the lake’s volcanic shoreline – about 20 metres out. Before I even get around to setting the hook the fly rod goes into a convulsive seizure and the fly line starts peeling off the reel. It slashes through the crystalline water surface – through the agitated and foaming waves, and soon after it is accompanied by alarming amounts of fluorescent yellow backing.

The fly reel’s tormented snarl won’t come to an end…

Out of the corner of my eye I see the contours of an ominous creature catapulting itself into the air approximately 60 metres out. It towers briefly above the roaring waves and lands on its back in a collision-like crash that sends sparkling droplets of water metre-high into the air – and shockwaves through my galloping heart. Afterwards, the backing continues to peel though the guides of my dangerously arced 9” 6-weight fly rod, while I try to calm my thinly worn nerves.

WHEN THE FISH FINALLY SLOWS DOWN and comes to a halt, the fight enters a new phase. Instead of racing towards deeper water, it now thrashes about in the surface doggedly trying to eliminate the inexplicable pressure and drag. I desperately lean back on the fish until the cork handle creaks and after a long stint of tug-of-war, I slowly start gaining the upper hand. The fish comes closer to shore, I recover the fly line, and soon I get a short glimpse of the fish in the crashing waves – it’s a sight that sends shivers down my spine. The fish is big — really big!

Brown Trout

Now, it’s all about keeping a constant pressure on the fish and remaining calm. The fly seems to be lodged solidly in the fish’ jaws, but the razor-sharp volcanic cliffs and rocks along the shoreline are disturbing. If the fish decides to seek cover under them, there’s no doubt it’ll be more than the cacophonically singing leader will endure. The fish isn’t tired out yet, but it doesn’t seem fully aware of the severity of the situation. At any rate, I succeed in bringing the fish close to the small point where our Icelandic guide has set up with the landing net.

WHEN THE FISH CAPSIZES in the surf and glides over the frame of the landing net, we can beach an ancient-looking warrior of a trout – a massive fish with a big cannibalistic head, a mighty tail blade, incalculable ink stain-like dots, golden flanks and big, staring eyes in front of flamboyantly metallic blue gill plates. The fish measures close to 93cm, and even though it isn’t quite as fat as most fish in the lake, it is probably close to 10 kilos. It is a veritable dream fish – one that makes my tense body bubble with euphoria and excitement.

My fishing buddy, Martin Ejler Olsen, who has followed the fight at close range, shoots a quick series of pictures with a smouldering and lead-heavy sky as a backdrop, and I quickly proceed to immerse the fish into the lake’s freezing cold water. Here, it re-orients itself, slaps its tail defiantly and disappears into the fading azure blue depts.

WE’RE AT THINGVALLAVATN; a massive lake resting below towering snow-clad mountains, in an ancient bed of barren lava plains and mossy meadows. It is early June, but it is still bitterly cold. And sharp, howling Northern winds agitate the lake’s massive water surface sending chilly waves crashing onto the rocky shores.

We have four days of fly fishing to look forward to, and already now – after our first expectant day on the lake, we have landed five incredibly beautiful brown trout more than five kilos. We have hooked the fish close to the shoreline, where deeper water meets the shallows, and they have perplexed us with their elegant colourations, and compact builds. These are regular Ice Age brown trout that can straighten out hooks, burst leaders and empty reels of backing with their sheer power and determination. The fact that they can grow to stupendous sizes only ads to their legend – and making Thingvallavatn what it is: A Jurassic Lake with brown trout.


THE THINGVALLAVATN BROWN TROUT are something truly unique. Their genetic makeup can be traced all the way back to England. From here, sea-run brown trout from the last Ice Age migrated to the Icelandic coasts and ventured into different watersheds and rivers. One of these waterways led the fish into an area that later on – because of massive volcanic activity 12,000 years ago – became isolated from the ocean. What is now Lake Thingvallavatn’s southern end rose and dammed what had previously been a roaring river. The now land-locked sea-run brown trout showed no signs of unhappiness being isolated from England and their home rivers, though. On the contrary, they quickly settled in the lake, and they grew in both size and numbers – even long after the first people found their way to the lake during the Age of the Vikings.

It wasn’t until a man-made dam in the lake’s southern end collapsed in 1959 that the unique brown trout stock suddenly started suffering. The spawning grounds, which were situated above the dam itself, ended up being destroyed as all the gravel was vacuumed and washed downstream. In the following decades, the trout stocks declined dramatically, and they ultimately ended up being on the brink of extinction.

The unfortunate development wasn’t reversed until the end of the last millennium. A group of passionate volunteers systematically started to rehabilitate the lake’s brown trout stocks. They electro-fished brood stock, and they succeeded in facilitating spawning activity in a handful of tributaries where the brown trout had never really spawned before. In 2000 progress was finally detected, and throughout the past 15 years, the Thingvallavatn brown trout have re-established and grown into a healthy population with strong genetics and sublime growth conditions. And as a result, the fishing in the lake is turning into quite the phenomenon!

THE AVERAGE SIZE of the Thingvallavatn brown trout is around a solid 3.5 kilos, and fish in the vicinity of eight kilos are caught on a fairly regular basis. Fish of more than 10 kilos are caught every year, and the standing record so far is an impressive 102cm fish that was estimated at 17 kilos. Lake Thingvallavatn’s brown trout are pure eating machines; chrome in appearance, broad and compact – and with ravenous appetites. They are among the most beautiful, well fed, and powerful trout in the world, and the key to understanding their impressive physique and growth rate is to examine the lake’s biomass and geothermic conditions.

First of all, Lake Thingvallavatn’s brown trout are mainly piscivorous – something that’s an obvious choice for them. There are four different sub-species of arctic char in the lake, all of which come in massive quantities, and together with the estimated 85 million sticklebacks, which flutter and swarm along the lake’s shores; the brown trout have access to a rich and high-protein food source.

Secondly, there are several places in the lake, where the fish are capable of hyper-effectively digesting whatever prey items they have just engulfed. Following their feeding sprees in the open water masses they simply head into one of the many geothermic areas, where tributaries and hot springs provide them with temperate water. Here, their metabolism is way higher, and they can digest their food up to ten times faster. With this routine in place, it rarely takes very long before the fish are back on the prowl. And since the process continues throughout the year, the fish display unprecedented growth rates.

Thingvallavatn Brown Trout

One last key to understanding why Lake Thingvallavatn’s brown trout grow so big is that they can get quite old – up to 15 years, and that their spawning habits are somewhat special. While brown trout elsewhere in the world spawn every year, it’s not uncommon for Thignvallavatn brown trout to get so preoccupied with feeding that they simply “forget” to spawn. It’s rather normal for Thingvallavatn brown trout to skip spawning every other year, and spawning pauses of up to three to four years aren’t unusual either. Furthermore, the spawning runs and breaks are relatively short, and this means that spawning doesn’t toll too badly on the fish, and that the spawning-related break from the feeding-fest in the lake is short-lived.

THE FISHING IN THE LAKE is very diverse. On calm days, for instance, you can experience some incredibly exciting sight fishing with nymphs and dry flies. In the mouths of some of the tributaries you can fish like in a river using cross current presentation, line mends, and strike-indicators. And when the wind is howling – which is does annoyingly often in Iceland – you can blind fish with streamers. It’s a rather arduous type of fishing, where you systematically search the shoreline for schools of fish with small, rapidly retrieved stickleback – and arctic char imitations – but it can produce some real monsters.

Access to the lake can be a little bit tricky since most of the shoreline is privately owned and there’s a significant lack of public roads. There is public access to the lake in the northern end – in the Thingvellir National Park. Fishing licenses for the national park can be bought via the national fishing license provider Veidikortid. (, and especially during spring and early summer, the fishing can be good.

The lake’s best fishing is without a doubt found on two beats managed by ION Fishing. Þorsteinsvík and Ölfusvatnsárósare the breakneck names of these two beats, and here you can experience what is probably the best brown trout fishing in the world. Because of stable water temperatures and closeness to deep water, the fishing is superb here – right from the season opening on the 20th of April until the season closing on September 15th. In total, four rods are available per day on a “fly only” and catch and release basis, and they are being sold for 300 Euros per rod (

Turbulent Endings

Hoarse winds seem to be forever sweeping the barren and twisted lava landscapes of Iceland. But as we round up the fishing at the ION Beats, the winds have picked up immensely – to the point of a raging storm. For the last two days massive, foaming waves pound the gritty lava shores of ION Beat I and II, and we struggle to even land a fly on the water. The fish are out there – we can see them boiling on the crashing waves, but they’re too far out.

We’re close to giving up, but as fate will have it, we’re lucky enough to be given one final window of opportunity. On our very last day, the winds unexpectedly die down and shift direction. The small, secluded bay that we’ve been fishing at Beat I calms down to the point that we can actually cast, and a giant school of brown trout ranging from two to eight kilos is suddenly within reach. A magical hour later, we have hooked and landed more fish than we can count. And while the real monsters that we’ve seen boiling in the waves earlier in the day elude us, we have caught more than a handful of fish that would make most brown trout fishermen anywhere morbidly jealous.

Thingvallavatn Brown Trout

As we pack up and leave, I’m swamped by ambiguous feelings. On the one hand, we’ve just experienced the best brown trout fishing of our lives. On the other hand, there’s this unlikely sense that we’ve only just scratched the surface: that Lake Thingvallavatn is capable of so much more. One week after returning, my gut feeling is confirmed. An Icelandic friend of mine has just experienced the ION Beats at their best – on a calm, ambient and temperate evening. Having landed numerous three to eight kilo fish topped by three incredibly well-built monster brown trout measuring 90, 95 and 101cm, he has probably experienced the best brown trout fishing any fly fisher will ever experience.

I’m still a little shaken by my experiences at Lake Thingvallavatn. And as I write this, I’m confronted with a lot of the questions that spun through my head as I boarded my plane in Reykjavik, left Iceland behind, and flew home. I particularly wondered if there was anywhere to go as a brown trout fisherman after having fished Iceland’s Jurassic Lake. As I conclude my writings, I’m more and more certain that the answer is “Yes, I can go back to Thingvallavatn!”



Thingvallavatn is situated half an hour’s drive from Reykjavik, and it is Iceland’s largest lake in both size and volume – with an area of 84km2 and water depths of up to 115 metres. The Thingvellir National Park is situated in the northern corner of the lake, and it encompasses the historic site, where the Icelandic parliament, Altinget, was formed back in 1930. The National Park is also the home of Silfra, a deep and fascinating fault line caused by tectonic plate movements, as well as Öxará, which is one of the main spawning grounds for the Thingvallavatn brown trout.

Thingvallavatn is somewhat of a geological phenomenon in that it is situated right where the Eurasian and North American tectonic plates meet. For this reason, there has been a lot of tectonic and volcanic activity in the area – something that has clearly marked and shaped the lake’s chaotic topography and surroundings. The lake is fed by rainwater. This water is filtered through the porous lava substratum and it slowly seeps into the lake, nutrient-rich and crystal clear. 90% of the lake’s water reserves are subaqueous, and as a result, the lake is fed by thousands of springs, which in turn cause the water temperatures to be quite stable – 3-4 degrees throughout the year.


The main airport in Iceland, Keflavik, is well-connected to the rest of the world, and depending on the season and time of departure, Icelandair ( offers plane tickets at around 150 – 300 euros.

The transportation to the lake takes about one hour from the airport, and a 4WD car isn’t necessary.

There are several options when it comes to accommodation, but if you’re planning to fish the ION beats, the comfortable ION Hotel ( is the most obvious choice.


The gear that is typically used in Lake Thingvallavatn is fairly stout – and with good reason! First of all, the weather is usually quite windy. Secondly, there’s quite a good chance of running into fish of frightening proportions, and thirdly the Thingvallavatn brown trout fight as if they were on a cocktail of steroids and speed.

When streamer fishing, a 9.6” #8 fly rod with a floating – or intermediate fly line and a 4-5 meter long 0.35mm fluorocarbon leader is suitable. The flies, that are most frequently used, are typically quite bulky, eye-catching weighted streamers in different sizes – from #4 – 2/0. The local favourites are streamers such as Black Ghost Zonker, Super Tinsel, White Nobbler and Black Brahan – and they are all flies that can imitate the sticklebacks and arctic char in the lake.

When it comes to the incredible dry fly- and nymph fishing on the lake’s ION Beats, a delicate and subtle presentation is often crucial. As a result the gear usually consists of a fairly compliant 9” 5/6-weight rod, a fly reel with a minimum of 300 metres of backing, a floating WF fly line, a 5-6 metre long leader with a 0.16-0.22mm tippet and small #12-18 nymphs and dry flies. It goes without saying that hooking into giant brown trout with such delicate gear involves some serious challenges. Oftentimes it simply results in spooled fly reels, straightened hooks, torn leaders, and broken hearts. The occasional lost fish, however, is a price a lot of fly fishermen are willing to pay to be able to sight cast to wild brown trout ranging from 5-10 kilos. Where else in the world is that even possible?

Words By: Rasmus Ovesen

Photos By: Rasmus Ovesen and Martin Ejler Olsen