Three Castles. One River. Fifty Unforgettable Kilometres.

One of the UK's largest and most popular 50km trail ultra marathons returns for 2027.

Join hundreds of runners from across the UK as you follow the beautiful River Medway on an unforgettable point-to-point journey through the heart of Kent.

Starting beneath the imposing walls of Rochester Castle and finishing with a victory lap on the athletics track in Tonbridge, the Three Castles 50km has quickly established itself as one of the country's favourite ultra marathons. Combining stunning riverside trails, medieval history, outstanding organisation and an incredible community atmosphere, it's a race that runners return to year after year.

Whether you're chasing your first ultra marathon finish or aiming for a new personal best, Three Castles offers the perfect balance of challenge, scenery and achievement.

Why choose the Three Castles?

The Three Castles 50km isn't just another ultra marathon.

It's a race designed to be accessible, memorable and professionally delivered from the moment you arrive until you cross the finish line.

The route is predominantly flat, making it one of the UK's most achievable 50km ultras for first-time runners, while still offering experienced athletes an excellent opportunity to run fast.

Supported by outstanding volunteers, four fully stocked aid stations, live GPS tracking and an unforgettable athletics track finish, every detail has been designed to give you the best possible race experience.

Why runners love it

• One of the UK's largest 50km trail ultra marathons

• Flat, fast and ideal for first-time ultra runners

• Three iconic medieval castles

• Beautiful riverside trails following the River Medway

• Four fully stocked aid stations

• Live GPS tracking and timing

• Fully marked course

• Epic athletics track finish

• Friendly volunteers and an incredible atmosphere

• Generous 9-hour cut-off

The Course

Follow the spectacular Medway Valley Walk from Rochester to Tonbridge on a course that perfectly blends history, countryside and fast runnable trails.

Beginning beneath Rochester Castle, you'll immediately join the banks of the River Medway before heading west through picturesque villages, peaceful riverside paths and open countryside.

Along the way you'll pass three magnificent medieval castles, historic locks, ancient bridges and some of Kent's most beautiful landscapes.

The route remains predominantly flat throughout, making it one of the most accessible 50km ultra marathons in the UK, while still delivering everything you'd expect from an unforgettable trail running adventure.

As Tonbridge comes into view, one final push leads you onto the athletics track where you'll complete a full lap before crossing the finish line to a huge welcome from supporters, volunteers and fellow runners.

What's Included?

Your entry includes everything you need for an exceptional race day experience.

✓ Fully marked course

✓ Professional chip timing and live GPS tracking

✓ Finisher's medal (for runners finishing within the official cut-off)

✓ Four fully stocked aid stations

✓ Medical support throughout the race

✓ Bag transfer from start to finish

✓ Epic athletics track finish

✓ Finish village with refreshments

✓ Awards for the top three Male and Female finishers

Time & Location

Registration

King's School Cricket Ground, Vines Lane, Rochester, Kent, ME1 1SX 

Registration opens at 07:00 and closes at 08:30.

During registration you'll receive your race bib, GPS tracker and drop bag label. Water, toilets and refreshments will be available.

The mandatory race briefing will take place at 08:35, before runners walk together to the start.

Start

Suffrage Sensory Garden, Esplanade, Rochester, Kent

To provide the best possible race experience and minimise congestion on the course, the Three Castles 50km uses a three-wave start.

Wave 1 – 09:00

Wave 2 – 09:15

Wave 3 – 09:30

Wave allocations are based on your estimated finish time, with the fastest runners starting first.

If you're planning to run with friends or clubmates, everyone must enter the same estimated finish time during registration. This is the only way to guarantee you'll be allocated to the same wave.

You may update your estimated finish time up until approximately two weeks before race day.

The overall race cut-off remains nine hours regardless of your start wave.

Finish

Tonbridge School Centre, London Road, Tonbridge, Kent, TN10 3AD

Official race cut-off: 9 hours

Every finisher completes one unforgettable lap of the athletics track before crossing the finish line.

Shuttle Bus

An optional shuttle service is available for runners travelling from the finish back to the start.

• £12 per person
• Runner-only service
• Limited to 250 places
• Departs Tonbridge School Centre at approximately 07:10

Further details will be sent closer to race day.

Checkpoints

Our incredible volunteer team will welcome you into four fully stocked aid stations throughout the course.

Checkpoint 1: The Friars, Aylesford Priory (13km)

Checkpoint 2: Maidstone Victory Angling Club (24km)

Checkpoint 3: Branbridges Leisure (34km)

Checkpoint 4: Racecourse Park (44.5km)

Each checkpoint offers water, soft drinks, Tailwind Nutrition, sweet and savoury food, fresh fruit and plenty of encouragement to keep you moving towards Tonbridge. All checkpoints cater for all dietary requirements and have female hygiene products on request.

Mandatory cut-off's apply at checkpoint 3 (6hrs 15mins) and checkpoint 4 (8hrs 10mins)

Mandatory Kit

All runners must carry:

• Mobile phone

• Minimum 1 litre fluid capacity

• Reusable cup

We also strongly recommend carrying:

• Waterproof jacket

• Hat or buff

• Sun cream

• Nutrition between checkpoints

• Bank card or cash

Mandatory kit requirements may be amended depending on weather conditions.

Event Rules

• To participate in this event, runners must be at least 20 years old on race day.

• Race bibs must be visible and securely attached to the front of your body throughout the event.

• Stay on the official marked course at all times. Any intentional shortcut will result in disqualification from this and future Embrace Ultra events.

• The challenge must be completed entirely on foot. The use of any other form of transport will result in disqualification.

• No storage of supplies or equipment is permitted anywhere along the race route.

• Only registered runners may participate. Pacers and buddy runners are not permitted.

• Crewing is only permitted at designated spectator locations, which will be published before race day.

• The event operates a strict 9-hour cut-off. Runners finishing outside the official cut-off will not receive an official result or finisher's medal.

• Each checkpoint also has a mandatory cut-off. Runners who fail to leave before checkpoint closure must surrender their race bib and will no longer be eligible for an official finish.

• If you withdraw from the race, you must contact the Race Director using the official event phone number and report to the nearest checkpoint as soon as possible.

• Dogs are not permitted to accompany runners on the course.

• The Three Castles 50km operates a zero-tolerance litter policy. Any runner found littering will be disqualified.

• For the safety and enjoyment of everyone involved, all participants must follow the instructions of the Race Director, event team, medical staff and volunteers throughout the event.

Course Records

Men's Course Record

James Macdonald 3:32:19 (2025)

Women's Course Record

Charlotte Johnston 4:21:37 (2024)

Race Permit

The Three Castles 50km is permitted by the Trail Running Association (TRA), an associate member of UK Athletics.

Permit Number: TBC

Other Information

• The route follows shared riverside towpaths and public trails. Please remain courteous to other users at all times.
• Several sections cross public roads or follow quiet country lanes. Runners must remain vigilant and only cross when safe.
• A drop bag service is included with your entry. Bags must be clearly labelled and left in the designated area during registration.
• At the finish, runners will have access to toilets, changing facilities, showers and refreshments.

Ready to Take on the Challenge?

Three castles.

One river.

Fifty unforgettable kilometres.

Join one of the UK's largest and most popular 50km trail ultra marathons and experience an incredible journey through the heart of Kent.

Saturday 5th June 2027

Embrace the Challenge. Conquer the Distance.