Time is running out for Londoners to secure a spot in one of the world's largest duathlons, which is taking place in the capital early next month.

The London Duathlon is held annually in Richmond Park and has become a popular fixture on the city's sporting calendar. Widely considered to be one of the world's premier mass participation run, bike, run events, around 4,000 people are expected to take part this year.

There is still time left to sign up for the 3 September event, but organiser Limeight Sports Club has seen strong demand for places – particularly among people travelling to south-west London from other parts of the city. The advice is anyone planning on taking part should book soon to avoid disappointment.

Entries close at midnight on 28 August – sign up now, visit: www.londonduathlon.com

Here's the ultimate guide to the event, and what to expect on the day.

What is the London Duathlon?

One of the world's largest duathlons – a run, bike, run event - and open to people of all abilities.

When and where is it?

The race takes part in beautiful Richmond Park in south-west London on 3 September. It's the capital's largest royal park and famously home to a much-love herd of deer. You won't find many more picturesque locations.

Sounds good. Is it too late to enter?

 No. Entries don't close until midnight on 28 August meaning there is still time to sign up. You can take part individually, or as part of a relay team with friends or family. And there are different distances to choose from. It's a great event, and a great spot to spend the day once you've finished your race.

What distances are there to choose from?

People can choose from three distance options: the half duathlon involves a 5k run, followed by a 22k bike ride, and a further 5k run; the full duathlon is double that distance (10k run, 44k bike ride, 10k run); and the ultra duathlon option challenges participants to run 20k, cycle 77k, and run a final 20k.

And the relay?

The relay, which is aimed at teams or two or three people, is a 10k run, 44k bike ride, and 5k run and has seen demand for places skyrocket this year as more and more people look to compete alongside friends, family, or colleagues. It gives people the chance to take part in a muti-discipline event without having to complete each leg themselves, with cyclists increasingly keen to team up with a runner friend, and vice versa.

I'd love to take part but don't have a bike.

That is not a problem. For events like this the organisers have teamed up with On Your Bike to offer a bike hire service. You just need to make sure you book it before 6pm on 29 August and your bike will be delivered directly to Richmond Park for you to use on the day. Details will be shared with all participants via email so keep an eye on your inbox.

So how do I sign up?

Don't delay; book your place now at: www.londonduathlon.com. Prices start from just £44 and if you live locally, you can also benefit from a 25% discount. Details are on the website.

How do I get my race pack?

You will need to collect it on the day of the race from the collection point in the event village. Everyone taking part will be sent an individual QR code in the week of the event, which will be scanned on the day.

All race packs will contain a number of essential items, including a security wristband, two bike numbers, a race number and a timing chip. For relay teams, the captain will pick up the race pack on behalf of the team.

What do I do with the different race pack items?

The race number goes on a participant's back during the cycle, and front during the run. They can be fixed with safety pins, but organisers recommend a race belt as it is easy to switch between the two.

The bike number stickers need to be placed on the front of your bike and top of your helmet, while the security wristband must be worn at all times; without it, you won't be allowed into the transition area.

The timing chips are reusable and must be worn on the left ankle. Once the race is finished, everyone taking part is asked to return their chip by putting it in the buckets at the finish line. There is a £25 charge for anyone who doesn't do so.

For the relay teams, the timing chip acts as a baton and must be passed between relay members throughout the race.

What time does the race start?

Participants will set off in different waves depending on their expecting finishing time. The first group will set off at 8.30am, with the last wave underway at 10.10am. Anyone taking part should arrive an hour-and-a-half before their start time to give themselves enough time to set their gear up correctly in the transition area, before warming up and making their way to the start line.

How do I get to the start line if I'm taking part?

Organisers LimeLight Sports Club always recommend using public transport where possible to get to its events to help reduce the environmental impact. The nearest tube station is Richmond, which also the nearest train station. It's about a half an hour walk to Richmond Park, or a short bus ride.

If you have to travel by car, there will be limited race day parking available in Richmond Park. LimeLight Sports Club will be in touch with everyone who has signed up to let them know how to book, with spaces offered on a first come, first served basis.

Is there a bag drop?

There won't be facilities for storing bags or valuables at Richmond Park, apart from in your transition area. Bags/boxes in the transition area must be kept to one bag per person with maximum dimensions of 50x50x50cm or 30L. Whilst there will be officials and marshals in the transition area, all personal items are left at the owner's risk.

How do I store my bike?

Bike storage will be well sign-posted on the day, with clear instructions on how and where to put your bike. You'll just need to leave yourself plenty of time to store your bike in the transition area before getting ready for the start. You won't want to being rushing things on the day.

Anything else I need to know about the cycling element?

Disc brakes are allowed, as are disc wheels, although the latter rule may be amended in the interest of safety in the event of strong winds.

Fixed wheel bikes are not permitted, and handlebars must not have bare metal ends – if your ones do, please get some stoppers to plug them before heading to the race.

Tri bars and handlebars must be plugged and must be secure. There is no requirement for them to be shorter than the brake levers, unlike in elite races.

This won't mean anything to everyone, but drafting is also against the rules for this event. This means you must not take shelter cycling behind, or cycle beside, another competition during the race. If you do, you may be disqualified. The draft zone is a rectangle measuring ten metres in length by two metres across. Basically, don't try and take it easy by cycling in someone else's slipstream.

Richmond Park is pretty busy with runners and cyclists at weekends. How will that work on race day?

That's one of the best things about the London Duathlon. For one day only the roads and trails throughout Richmond Park, including the Tamsin Trail, will be closed to all vehicles and non-event cyclists.

The event is one of very few closed route duathlons in the UK – making it a must-attend for people chasing personal bests, but also a great experience for less confident participants or those looking for a more relaxed environment to race in.

Is the event good for spectators?

It's brilliant for spectators. Not only do they get to watch you compete, but they can also enjoy the picturesque surroundings of Richmond Park.

The best place for them to watch from is probably the event village, which is at the Roehampton Gate end of the park.

As well as a great place to watch from, there will also be food and refreshment stalls and toilets.

Will there be aid stations on the course?

There will. As well as seven emergency and treatment units dotted regularly throughout the course, there will also be a number of water stations on each run route. There will also be a water stop on the bike route, but only for ultra distance participants.

You'll need to bring your own refillable bottle – the organisers won't be providing single use cups as part of their commitment to reducing the event's impact on the environment. 

Can I listen to headphones while racing?

The short answer is no. The longer answer is organisers don't allow them because wearing headphones can make it hard for participants to hear important instructions from event marshals.

Not to worry though. It's better without headphones anyway; you get to soak up the encouragement from spectators.

The event sounds great – is there a way I can help out if I'm not taking part?

LimeLight Sports Club is always looking to expand its team of volunteers, the LimeLighteers. They're guaranteed a fun day, with plenty of support, with food and refreshments provided. They'll also have local travel costs reimbursed as be offered free or discounted entry for one of LimeLight Sports Club's 2024 events, which include the ASICS London 10k, the Wizz Air Hackney Half Marathon, and Challenge London.

Interested? Email: [email protected] for more information.

Inspired but can't make this year's event?

Don't worry. Places for the 2024 race will go on sale soon, so keep an eye on the organiser's website at: www.londonduathlon.com.