Running the Thames Riverside 20
Spring marathon tune-up race on a fast, flat River Thames towpath
The Thames Riverside 20 is an annual event that takes in 20 miles of beautiful scenery along the River Thames towpath, starting near Richmond-upon-Thames, heading west to Teddington and then east to Chiswick and back to Richmond.
Organised by the Clapham Chasers Running and Triathlon Club, the race takes place in mid-March. Running the Thames Riverside 20 is an excellent way to get in a more ‘pleasurable’ long run prior to a Spring marathon, coming a month before the London Marathon, three weeks prior to the Manchester Marathon and two weeks before the Brighton Marathon.
Oh, and did I mention the cake? The Thames Riverside 20 is famous for its post-race cake sale, with a sumptuous selection of delicacies available so you can start piling the calories back on immediately!
So if you’re thinking about running the Thames Riverside 20, here’s what you can expect.
Pre-race Organisation
Race sign-up was very easy through the organiser’s website on Eventrac, with a decent amount of information, including course maps and participant information.
In the 2023 edition however, there were a series of challenges the race organisers had to overcome, not least the awful British weather threatening to scupper the entire event until just a few hours before the gun.
For whatever reasons, Clapham Chasers also seemed to be struggling to fill places for this event, offering a series of offers to drum up further entries in the lead up to the race. In the end, 315 people finished the race, which was a decent turnout considering the conditions…
…because in the week leading up to the Thames Riverside 20, the weather was awful. It rained non-stop for days on end, and the Friday before the race, the Race Director made the call to re-organise the start as Old Deer Park was completely flooded.
After another downpour the night before the race, it was still apparently touch-and-go as to whether the event could take place, but after a 20-minute delay to the start time to allow for more drainage on the course, the gun went off and we eventually got started running.
So the pre-race organisation was not ideal, but in fairness it’s probably the best everyone could have hoped for given the circumstances.
Thames Riverside 20 Course Profile
The Thames Riverside 20 is, as the name suggests, a 20-mile race along the River Thames. Starting in Old Deer Park, Richmond-upon-Thames, the course heads immediately out to the river towpath and tracks south and west along predominantly concrete and tarmac surfaces.
As the course reaches Teddington, it takes a left-hand turn away from the river and along the streets of Ham for several miles, before turning left again at Ham House and back towards the towpath. The route then takes another left and retraces the same route through to Teddington and back to Ham House, before turning right at the towpath and back towards Richmond-upon-Thames.
After passing Old Deer Park, the terrain changes to trail, and in the 2023 edition of this race, due to the rain, it was littered with puddles.
The route heads past the Royal Mid-Surrey Golf Club, skirts by Kew Gardens and on to Chiswick Bridge, before doing a 180-degree turn and going back the same way to Old Deer Park.
Due to the flooding in Old Deer Park in the 2023 running of the Thames Riverside 20, the route actually went down the stairs at Twickenham Bridge after the first half mile, which meant a rather mean stair climb at 19.5 miles to get to the finish line. But after seeing how flooded the original route was at Old Deer Park, this change was pretty much the only option if the race was to go ahead.
Even with climbing two flights of stairs, the elevation gain for the course was only 177ft, so in a ‘normal’ year this will be one of the flattest 20-mile routes you’re ever likely to run!
Old Deer Park Start Village
The Thames Riverside 20 starts in Old Deer Park, where several tents were set up housing the Race HQ. Race information, bibs and bag check were all located there, along with a ‘spare’ tent to house a few dozen runners seeking shelter from the elements. There was a decent bank of toilets available at Race HQ, although the line did become long very fast as the start time approached.
Thankfully there was a large train station car park just over the road, so you could head back to your car to stay warm and dry until the race was ready to get going.
The spare tent turned into the ‘cake tent’ after the race, selling a big selection of homemade cakes in exchange for charity donations.
Old Deer Park to the Towpath
In ‘normal’ years, the Thames Riverside 20 will wind through Old Deer Park towards the towpath alongside the River Thames, but due to flooding before the 2023 running, the first half a mile was re-routed towards Twickenham Bridge. This meant having to leap down two flights of stairs to reach the towpath, which while not ideal, was certainly preferable to running through knee-deep water.
Teddington
The first four miles of the Thames Riverside 20 take you along a predominantly tarmac and concrete towpath towards Teddington. There are plenty of marshalls on the route, so you’re never in any danger of taking a wrong turn or not knowing about any potential hazards.
This section is entirely off-road, and while there were other towpath users, you didn’t need to worry about cars or crossings, so it was easy to settle into your stride and focus on your race plan.
Ham
After turning left at Teddington and heading away from the towpath, you follow roads for two miles heading towards Ham House. The 08:00 start to the race meant that the roads were very quiet, and with marshalls at virtually every crossing there weren’t any issues with vehicles.
After reaching Ham House, the course turns left and goes through a car park back towards the towpath, before following the same route through to Teddington, back to Ham House and back towards the towpath.
Lap 2
By the end of Lap 2 through Teddington and Ham House you’re at the halfway point in the race, with 10 miles logged already. The course then goes back along the towpath the same way you came in the first few miles of the race, and past Twickenham Bridge towards Chiswick.
Chiswick
The terrain on the route towards Chiswick gets gradually more trail-y, until you’re pretty much running on earth (and in 2023, through ankle-deep puddles!) I imagine this section of the Thames Riverside 20 is beautiful on a nice day, going past the Royal Mid-Surrey Golf Club, Syon Park on the opposite side of the river and Kew Gardens on its way to Chiswick Bridge.
In the 2023 running, it got to a point about 13 miles in where I just stopped trying to scoot around puddles and started to plough through them — I was drenched anyway and they were too big and too numerous to be jumping around trying to dodge.
The turning point at Chiswick Bridge comes at 15.5 miles, and while I had a degree of trepidation that I needed to navigate those puddles once again on my way to the finish line, at least seeing the 16-mile marker means you know it’s only a little further than a Parkrun to go!
Final Push
The final push comes as you reach Twickenham Bridge, this time heading up two flights of stairs before running your last half mile to the finish line. Mercifully, the gradient from the top of the stairs is downhill along Twickenham Road, before a sharp left-hander on to the grass at Old Deer Park to finish under the same arch where you started.
Race Strategy
I was running the Thames Riverside 20 as a tune-up race for running the Boston Marathon a month later, so I had a race plan in mind early on that came from my running club, the Sutton Striders.
The previous weekend I’d run the Kingston Spring Raceday 20-miler, so the plan for the Thames Riverside 20 was to run slightly slower than my target marathon pace, but to run even splits throughout at 7:00 mins/ mile.
Clapham Chasers had two pacers running 7:00 mins/ mile, so I decided to stick with them for as long as I could.
There were about 15 people tagging along with the 7:00 mins/ mile pacers for the first few miles, but by the time we reached 19 miles there was only me and one other runner. The pace had been consistent throughout, but I suspect we picked it up a little towards the end after turning at Chiswick Bridge. Not that it mattered for my particular goals, it was good to get a bit of a push in the last few miles.
At Mile 19 I decided to crack on a little and ran ahead of the pace group, finishing in 2:18:58 and an average pace of 6:57 mins/ mile.
Reflections
Super long-runs during marathon training can be a real drain, especially if the weather is awful and you’re running by yourself. This is one of the reasons I’m thankful the Thames Riverside 20 went ahead, despite the weather and organisational challenges, as I’d have been running 20 miles that day anyway, and it was much more ‘enjoyable’ doing it as part of an event!
The weather was the big drag on the 2023 event from a participant’s perspective, as it was still raining and windy an hour before the race. It wasn’t ideal that the start was delayed by 20 minutes, but if the decision was to have a short delay or cancel the race, I’d much prefer the delay.
The route is very scenic and flat as a pancake, which means you can really focus on your pace and enjoy it. The pacers (certainly at 7:00 mins/ mile) held a constant pace throughout, which gave you even more headspace to focus on your race technique.
Running a 20-miler is not something I’d typically do for fun, but as part of a Spring marathon training programme the Thames Riverside 20 is perfectly timed and, weather permitting, should ordinarily be a wonderful experience. It’ll certainly go into my race calendar if I’m running a Spring marathon next year.
If you’ve liked this race report, you can check out my other reports on Running the New York Marathon, Running the Berlin Marathon and Running the Athens Authentic Marathon.
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