The toughest 9 half-Ironman distance triathlons on the planet

For many, taking on a middle-distance triathlon is hard enough, but what if you want to make it extra challenging? Well, then you’d probably want to take on one of the toughest 70.3 races in the world…

To help you on your masochistic pursuit of a challenge, we’ve pulled together a list of middle-distance races that’ll really test you. Follow a targeted 70.3 training plan to prepare yourself for one of these exciting challenges.

Best middle-distance triathlon races

1. The Gauntlet

Location: Hever Castle, Kent, England

Next race: 26-27 September 2026

The Hever Castle leg of the Castle Race Series is famous for hosting the world’s largest children’s triathlon and more beginner-friendly races than you can poke a track pump at. But what’s often overlooked is how deceptively tough the bike and run routes are of the longer races.

After a unique 1.9km swim that features a Japanese teahouse and two bodies of water (a lake and a river Eden tributary), the Gauntlet’s 90km two-loop bike takes in the high weald of Kent and Ashdown forest. It’s relentlessly rolling and scenic (if you can muster the energy to sightsee), with the high/low point being the 7km-long climb on the High Road south of Hartfield.

The two-loop run, meanwhile, is set on leg-sapping trails and bridle paths to Chiddingstone and back, and is one that’ll keep you on guard throughout and can be very sticky if it’s rained before the race. There’s also a nasty little climb at the end of each loop before one of the UK’s best finishing chutes (and post-race food).

2. Challenge Walchsee-Kaiserwinkl

Location: Walchsee, Austria

Next race: 28 June 2026

Set in the majestic Austrian Tyrol region, Challenge Half Walchsee-Kaiserwinkl gives Challenge Wanaka a push as the race organiser’s most beautiful event. But, like that New Zealand stunner, there’s a sting in the tail provided by the testing bike leg.

After a swim in the crystal-clear Walchsee lake, the two-loop 90km bike takes in the mountainous panorama of the Kaiserwinkl region, subjecting athletes to over 1,000m of elevation gain along the way. The 21km run course is mercifully flat and heads around the lake, along the promenade and through alpine meadows.

3. Israman 113

Location: Eilat, Israel

Next race: 27-30 January 2027

Israman began life in 1999 and remains the only long-distance triathlon in the Israel’s dedicated multisport scene. Hosting both 113km middle and 226km long-course races, the Israman starts in the southern holiday resort of Eilat, nestled between the mountainous terrain of Jordan to the east and Egypt to the west.

The race then heads north after a swim in the salty Red Sea for the unforgiving Negev desert, starting with a 12km climb straight out of transition up to 600m above sea level. The temperatures in the desert can vary from freezing to 30C, with 60mph crosswinds adding to the gruelling mix.

If the run elevation gain looks small, that number is deceptive (so we’d added a few marks), with the course unique in middle-distance triathlon in that it’s sharply downhill for the first 12km before a coastline finish.

4. Snowman Triathlon

Location: Plas y Brenin, Snowdonia, Wales

Next race: 26 July 2026

If snow is unlikely in July, even in the seeming microclimate that is Snowdonia, the Snowman delivers on its promise of being top race organiser Always Aim High’s toughest middle-distance race.

The swim kicks off in the shallow Llyn Mymbyr before an epic 90km bike through the heart of the Snowdonia National Park. The run nearly features as much elevation gain as the bike, taking athletes to the summit of Moel Siabod and straight back down to the finish line at Plas y Brenin.

There’s now an 86km middle-distance triathlon that still offers a decent challenge and an opportunity to test your fitness.

Altitude more than elevation gain plays a major role in the athlete’s toils, with the swim taking place in an artificial lake at an altitude of 2,000m.

The bike then climbs even higher on the bike course into the Querétaro Mountains. The run is thankfully flat but the mid-summer Mexican sun keeps the torment coming.

Triathlon San Gil 86k stats

	Info	Tough score
Swim type	altitude lake	8
Swim temp	22°C	5
Bike elevation	787m	2
Run elevation	62m	2
Run surface type	road	5
Average high temperature	27.4°C	10

6. The Lost Sheep

Location: Kenmare, Ireland

Next race: 29 August 2026

Location: Aurland, Norway

Next race: 15 August 2026

If a race start on Laguna Beach conjures images of Thailand, the AxTri’s setting couldn’t be further from it. The Aurland fjord is one of the deepest in the world and water temperatures range from 8-20C depending on the depth.

The long 98km bike route boasts 3,100m of elevation gain and travels from Aurland, over Aurlandsfjellet (1,320m above sea level), down to the village of Erdal by the fjord, back the same way over the mountain to Aurland and the eastern end of the lake Vassbygdi-vatnet (T2). The air temperature may drop below the freezing point on top of the mountain on the bike leg, even in August.

Athletes have a 2km respite from the hills at the start of the run before things get hilly for the final 19km, with over a thousand metres of climbing. Support crews are allowed to follow athletes up the valley, but each athlete must carry their own backpack containing all their gear. The run up Aurlandsdalen has seen temperatures close to 30C, so athletes have to prepare for all weather conditions, as well as aching calfs, quads and lungs.

AxTri stats

	Info	Tough score
Swim type	fjord	10
Swim temp	8-20°C	10
Bike elevation	3,100m	10
Run elevation	1,100m	10
Run surface type	trail	7
Average high temperature	14°C	8
Psych battle		10
Isolation		10
DNF rate	3.44%	3
Median time	9:02:24	9
Tough total	87/100

9. The Brutal Half

Location: Llanberis, Wales

Next race: 19 September 2026

Set in the picturesque and dramatic scenery of Llanberis in Snowdonia, Northern Wales, the Half Brutal is the shortest brother of the increasingly (in)famous Brutal family, which also include the full length (up there as the toughest Iron event on the planet, the double and triple.

The swim section takes place in the chilly Lyn Padarn lake’s water (two laps). What follows is worth the race name: a two-lap bike with 1,524m of total vertical gain in total, one 8km lap of running around the lake to stretch the legs, and then a leg-sapping, lung-busting climb to the top of Mount Snowdon, the highest mountain in Wales, and back down again.

Brutal Half stats

	Info	Tough score
Swim type	lake	7
Swim temp	15°C	8
Bike elevation	1,513m	7
Run elevation	920m	9
Run surface type	mountain paths	9
Average high temperature	14°C	8
Psych battle		10
Isolation		10
DNF rate	12%	10
Median time	10:40:53	10
Tough total	88/100

• Ironman-distance triathlons: The best European Irons for beginners

• Middle-distance triathlons: The UK’s best half-irons for beginners