The best triathlons in the UK
From beginner races to ultra challenges, swim-bike-runs are the UK's favourite multi-sport events - these are the triathlons that you need to have on your radar.
Triathlons are some of the most popular active outdoor events in the UK, ranging from major races in city centres to off-road events exploring the great outdoors.
The combination of swimming, cycling and running is both a serious endurance challenge and a fantastic opportunity to immerse yourself in stunning natural environments, experiencing them as you simply can't with a single activity event. From the rapid changes in pace to the strictly-observed transitions, triathlons are an event like no other.
All of which goes some way to explaining why there are so many of them in the UK. There are nearly 600 triathlons listed on TimeOutdoors, with more being added all the time. Within that list is a diverse range of novice races and endurance ultras, along with everything in between.
To help you get started, we've compiled a list of some of our favourites - swim-bike-runs that provide an epic race experience and are asset to the sport. If you think we've missed anything out, let us know!
Beginner triathlons
These swim-bike-runs are designed for first-timers and often feature a pool swim to help you build confidence.
Tavistock Triathlon
The 'Go Tri' race at this popular South West triathlon event is perfect for anyone who has never taken part in a swim-bike-run before. The 300m swim is held in a 50m Olympic swimming pool, providing a well-managed environment to help build confidence. From there, the 12K ride sets out onto quiet country roads and the 2.5K run takes place on an old railway line.
Castle Howard Triathlon and Multisport Festival
The epic grandeur of this event venue is one great reason to sign up - the festival village is hosted in the grounds of this North Yorkshire castle, providing a spectacular backdrop to the race. In the Starter Triathlon, you will swim in the Great Lake in the castle grounds, cycle through the Howardian Hills and run through the grounds, culminating in a sprint finish in front of the main doors of the house!
Eton Dorney Family Triathlon
A purpose-built rowing lake that is owned and managed by Eton College, Dorney Lake is a popular venue for triathlons all year round and hosts this Family Fun Triathlon. The 100m open water swim is followed by a traffic-free, 1.5K bike ride and a final 600m run that is held on a spectator-friendly course. The whole event is managed to be great fun for the whole family.
Super sprint triathlons
These short races usually include a 400m swim, 10K bike ride and 2.5K run, though distances can vary slightly, making them very suitable for beginner triathletes.
Brighton and Hove Triathlon
This is one of the biggest and most popular events in the UK triathlon calendar, enjoying a mass start to the sea swim for each race and a fast, flat and traffic-free seafront course. Those conditions mean that the super sprint event is ideal for both beginners and anyone looking to pick up the pace, with over 250 prizes on offer across all categories.
The Herefordshire Triathlon
Having been organised by the Hereford Triathlon Club for three decades, this traditional swim-bike-run is a stalwart of the triathlon season. After a 400m swim in the 25m Leominster pool, athletes will then cycle for 12 miles along an undulating course before running for three miles along the roads through the town, allowing for support from local crowds in those last few miles to keep you moving.
Felixstowe Triathlon
This event was the winner of Triathlon England's Large Event of the Year award, so you can expect a well-managed and marshalled race! After a brisk 300m pool swim, the 20K bike ride explores the beautiful Suffolk countryside, returning via the Felixstowe Ferry for a final 3K run along the promenade to finish things off. There are two other distances on offer, so stick around to cheer on the athletes and enjoy the event village.
Sprint triathlons
Clocking at the half the distance of an Olympic triathlon, these races include a 750m swim, 20K bike ride and 5K run.
Dartmouth Triathlon
This is an incredible location for a triathlon, with participants exiting the sea swim to embark on an out-and-back bike ride that features Devon's flattest road, before rounding things off with a run along the Blackpool Valley Road. The route has been edited to avoid a road crossing and this ninth edition of the race looks to be better than ever. Plus, there is an option to camp on the beach nearby!
Windermere Triathlons and Duathlons
The Lake District is a sensational setting for any active event but triathlons are able to experience the full range of its natural beauty. After a short swim in the pristine waters of Lake Windermere, the cycle heads up to Ambleside and back, with some undulating terrain on the way. The run then takes place on a multi-terrain route, with a mix of tarmac, trails and grass.
Sun City Triathlon
The North Sea makes for a bracing sea swim but this event is held when the water is at its warmest, so it should be very manageable. The bike ride features four laps of a 5K course, allowing speed demons to really start racing, after which a single lap of the course hosts the 5K run. The exciting beach start helps to make this Sunderland triathlon a fan favourite.
Olympic triathlons
As the name suggests, this is the official distance used in the Olympic Games: 1.5K swim, 40K bike ride and 10K run.
London Triathlon
With 13,000 triathletes arriving each year, this is one of the biggest swim-bike-run events in the world. The 2012 Olympic venue, the ExCel, plays host to the weekend's races, including this flagship race: the Olympic distance triathlon. After a swim in the London Docklands, you'll transition to a bike ride following the course of the Thames and enjoying views of London's iconic landmarks. The final run will take place within the ExCel itself.
Bluestone Pembrokeshire Coast Triathlon
The Pembrokeshire Coast National Park is a place of extraordinary natural beauty, which this Olympic distance triathlon takes full advantage of. After a brisk sea swim, triathletes head out onto rural roads for the bike ride, with some fast and flat sections but also over 400m of climbing. The run explores the Pembrokeshire Coast Path and culminates in a beach finish!
Birmingham Triathlon
The UK's second largest city hosts the Birmingham Triathlon for the second time in 2023, with an option to compete on your own or enter as a relay team. This triathlon is hosted in Sutton Park and the swim takes place in Powell's Pool, which was used for the 2022 Commonwealth Games. After that, both the bike ride and run enjoy closed roads through the park, surrounded by heathland and ancient woodland.
70.3 triathlons
Also referred to as 'half' distance or 'half Ironman', these triathlons are a total of 70.3 miles: 1.2 miles swimming, 56 miles cycling and a half marathon at the end.
Hever Castle Triathlon and Multisport Festival
Another edition in the Castle Race Series, this event takes place in the Tudor palace that both Anne Boleyn and Anne of Cleaves once called home. The Gauntlet is their half Ironman distance triathlon, with a swim that dives into the castle's lake and a bike ride that explores the surrounding Kentish countryside. The half marathon returns to a bustling festival village that connects all the races taking place!
IronBourne Middle Distance Triathlon
Eastbourne is the location for this pair of endurance triathlons, with a full distance swim-bike-run on offer too. You will dive into the English Channel from the end of the historic pier, transitioning afterwards to a bike ride through the South Downs National Park. The half marathon enjoys great seaside views from the town's promenade, making for a fast and flat route. There is a fantastic event village with plenty of other races on offer, too.
The Roc Scotland
Described as a 'progressive' triathlon, this race doesn't follow the typical swim-bike-run format - well, it adds another 'bike-run' onto the end to create a five-stage race. What's more, the cycling is gravel riding to the foot of Ben Nevis and the run involves climbing to the summit and returning, creating a truly monumental challenge. There are events that tackle Snowdon and Scafell Pike too, if you're interested!
Ironman triathlons
Also described as a 'full' distance triathlon, these clock in at a 2.4-mile swim, 112-mile bike ride and a 26.2-mile run.
The Northumbrian
Based in the far north of England, in the wild expanse of Kielder Forest, this full distance triathlon is a serious endurance challenge. The swim takes place in Kielder Water, the largest man-made lake in northern Europe, while the bike ride heads up to the Scottish border across undulating hills. Finally, the marathon is run on hard-packed trails around the reservoir and through green pine forest.
Outlaw Nottingham
This full distance triathlon is hugely popular not just for its fast course but also for the festival vibe to the whole weekend, with on-site camping for those who are up for a party! Based at the National Water Sports Centre at Holme Pierrepont, this swim dives into the Regatta Lake and there are great opportunities for spectators to cheer on athletes around the bike ride and run.
Ironman UK
The UK's only official IRONMAN® event, this is one that you can't miss if you're interested in ultra triathlons. Held in Bolton, the route explores some of the North West's most stunning scenery on the bike course and returns to the city centre to rapturous support for the marathon and finish line. The atmosphere and sense of occasion at an IRONMAN® event is unforgettable.