What are the best Olympic triathlons in the UK? We rate our top 10 races to get your teeth into next season
Looking for a Standard distance triathlon to dip your feet into the world of tri? We’ve picked 10 of the best Olympic triathlons in the UK, plus some last-season European wildcards.
The UK is blessed with a packed calendar of Olympic-distance triathlons, a challenge that’s ideal in difficulty for most levels of triathlete.
Consisting of a 1.5km swim, 40km bike and 10km run, Olympic or Standard distance triathlons can be held in city centres, boosting the atmosphere and facilitating logistics, as well as more rural settings. Generally, organisers offer shorter distances on the same day, but check out our dedicated guide to the best sprint and supersprint triathlons in the UK for more options.
1. Royal Windsor Triathlon
- Date: 13 June 2027
- Location: Windsor, Berkshire
- Entry fee: £99
The Royal Windsor is one of the UK’s hottest triathlon entries, and usually sells out. The fact it’s a good course for PB and that you swim past the King of England’s house has much to do with that. The swim is in the River Thames, followed by a scenic bike leg through the Berkshire countryside, finishing with a 10km run on the iconic Long Walk towards Windsor Castle. You’ll tackle the leg-burning Castle Hill three times. Plus for those with short course friends, there’s a sprint-distance race that runs on the same day.
2. London T100
- Date: 21-22 August 2027
- Location: Royal Victoria Dock, London
- Entry: £208
The London T100‘s 1.5km swim comprises one lap of the freshwater course in the Royal Victoria Docks. The closed-road bike course heads west along the Thames, taking you past landmarks like Big Ben and the London Eye, before turning back on itself. To finish, you’ll complete three laps of the 3.3km run course between Royal Victoria and Royal Albert Docks. The 100km, sprint, and super-sprint distances take place on the same weekend.
3. Cardiff Triathlon
- Date: TBC, usually July
- Location: Cardiff Bay, Wales
- Entry: £115.99 (2025 price)
The Olympic-distance triathlon in the Welsh capital is also flat and fast. It didn’t run in 2026 due to developments in the Cardiff Bay area where the swim takes place, but organisers have hinted at its return.
After the swim, you then undertake the four-lap bike leg, passing the Millenium Centre, the Senedd and Cardiff Bay again. On the run, you go out and back to the Barrage twice.
Like most city-centre triathlons, the Cardiff Triathlon promises supportive crowds and fast times. You can also pick from Sprint and Middle distances, and a duathlon. Read 220 contributor Rob Slade’s Cardiff Triathlon race report from 2025.
4. Slateman Triathlon
- Date: 13 June 2027
- Location: Llanberis, Eryri (Snowdonia)
- Price: £114.99 (Tier 2)
The Slateman is renowned (or should that be feared) as one of the UK’s toughest triathlons owing to its mountainous bike and run courses in craggy Eryri (Snowdonia). On the day, the Olympic Distance is one of the shortest courses, but it’s still a formidable test.
Llyn Padarn hosts the 1.5km swim at the base of Wales’ highest mountain, Yr Wyddfa (Snowdon). On the bike, you wind around it before scaling Gwynant Pass on the way back to Pen Y Pass. The Slateman earns its name from the Dinorwic Slate Quarry you pass at the start of the run and weave through on a 2km climb. It’s nearly downhill from there, but the terrain is pretty technical. Distances range from Sprint to Full Distance, and Standard Duathlon.
5. Eastbourne Triathlon
- Date: 11 July 2027
- Location: Eastbourne, East Sussex
- Price: £139
Triathlon locations don’t get much more breathtaking (figuratively and literally) than Eastbourne, in the coastal South Downs. You’ll swim for 1.5km backdropped by Eastbourne Pier. The rolling bike course consists of two 20km laps with 700m elevation, including an ascent of Beachy Head. The 10km run along the seafront is much flatter. You can also do Super-Sprint, Sprint and Middle distances.
6. Croyde Ocean Triathlon (Olympic)
- Date: 11 July 2027
- Location: Putsborough Sands, North Devon
- Price: £99 (early bird)
The Croyde Ocean Triathlon also lays claim to being the UK’s hardest standard-distance triathlon. The Atlantic Ocean often makes for choppy swimming conditions and slow speeds. Nearly 700m of elevation is packed into the 38km bike and you’ll climb a further 335m in the 12km multi-surface run. It does feature glorious views of the Taw Estuary if you can see straight enough to take them in.
7. Hever Castle Triathlon
- Date: 26-27 September 2026
- Location: Hever, Kent
- Price: £125
The Hever Castle Triathlon is one of the UK’s most popular and welcomes 7,000 participants across the multisport weekend in spectacular surroundings. You walk to the lake swim through the Italian loggia in the heart of the grounds. The varied bike course through the High Weald, an Area of Outstanding Natural Beauty, includes climbs, flats and descents but the off-road run in the castle grounds is arguably the highlight.
8. Dorney Lake Triathlon
- Date: 26 August 2026
- Location: Eton College Rowing Centre, Windsor
- Price: £99
Dorney Lake was purpose-built for 2012 Olympic rowing events and this is where you’ll do the two-lap, 1.5km swim. Running on either side of the lake, the pan-flat, traffic-free bike and run courses are ideal for a fast triathlon time or PB. Super-sprint and Sprint distances are also on offer.
9. The Snowman Triathlon
- Date: TBC for 2027
- Location: Capel Curig, North Wales
- Price: £115.99
The Snowman is another grippy multi-terrain, North Wales triathlon organised by Always Aim High. The Standard distance sends you on a freshwater swim in Llynnau Mymbyr overshadowed by Yr Wyddfa (Snowdon), a mountainous 69.3km bike leg, and a similarly hilly 8.7km run. On this last leg, you ascend to 872m before plunging back towards the lake.
10. Supertri Blenheim Palace
- Date: 5-6 June 2027
- Location: Woodstock, Oxfordshire
- Price: £121.99
The Blenheim Palace Triathlon has a UNESCO World Heritage site for a backdrop on the swim and beautiful views on the bike and run in the sprawling Estate. Although the race was bought by Supertri in 2026 and is technically now a sprint-distance race (750m swim–20km ride–5km run), we still wanted to keep it in as a good B-race option leading up to the big day.
Top three European Olympic triathlons
11. Hamburg Wasser Triathlon
- Date: TCB for 2027
- Location: Hamburg, Germany
- Price: €100-130
Part of the WTCS event series, the Hamburg Wasser Triathlon is said to bring 10,000 participants and enormous crowds to Germany’s second city. You’ll pass under a dark tunnel in the 1.5km Inner Alster Lake swim, before transitioning to a twisting inner-city bike course, and then finish the 10km run in front of the City Hall.
2. Ocean Lava Lanzarote
- Date: 24 October 2026
- Location: Lanzarote, Spain
- Price: €85
Ocean Lava organises triathlons all over Europe and its event on Lanzarote, the island of volcanoes and multisport training camps, looks like a highlight. You’ll enter the sea at Puerto del Carmen for a single 1.5km circuit, then take on an out-and-back bike route. The final run leg hugs the coast for two laps.
3. Challenge Barcelona
- Date: 24-25 October 2026
- Location: Barcelona, Spain
- Price: €89
The Challenge Barcelona is another late-season Spanish triathlon held on the coast of the Catalan capital. From Mar Bella beach, you swim a 1.5km lap in the sheltered bay. The bike route sticks to the shore for four fast and flat laps, and the run follows the Barcelona promenade for two circuits.
Head to our guide to the UK’s best Iron-distance triathlons for longer race options!
Jack Evans