Bwrlwm Bermo/Hurly Burly

The fastest 10k you'll find: fun, messy and the best way to start a summer of swimming


The first for the 2021 season with a 10k run and swim in North Wales: with mountains, a clear sandy estuary and a fast tide pushing you on, this is the fastest 10k in the land – with  run-swim and run options too.



Set in North Wales on the edge of Snowdonia, this is the most beautiful swim we have ever found. It starts on the sandy beach of Barmouth, and takes swimmers underneath Barmouth Bridge, a mile and a half wide iconic railway bridge. The first part of the swim is up the wide and sandy estuary with mountains on either side, and then it’s through ‘the narrows’ and into a more sheltered part of the estuary.

The whole swim takes place on a fast incoming tide that works like a bore to assist your swim. Past the narrows the water speeds up further, and the landscape becomes pastoral, the banks closer to you. Runners will run alongside the estuary on a flat gravel track, taking in the spectacular view along the way.

For those who fancy a challenge, there is the chance to take part in The Outdoor Swimming Society’s only Run-swim event. Run-swimmers will run from Penmaenpool to Barmouth, take a break and then join the main swimming event.

The swim and run ends at Penmaenpool, to change, gather for hot food warm up on fire pits and in hot tubs. Our swims are always about the journey and what a journey this is. It took us 7 years of looking to find a swim route that rivals the Dart 10k, and this is it.  Read more about the 2018 event in the event report and gallery.

Jess Rose
Vivienne Rickman Poole
Jess Rose
Jess Rose
Jess Rose
Jess Rose
Jess Rose
Jess Rose


This swim is heavily tide-assisted, and it takes swimmers around 75-150 minutes to complete the 10k course as a result. The degree of challenge in this swim depends very much on the weather on the day. On a sunny clear day, the sandy bottomed estuary can look like the Mediterranean. On a bad weather day, with choppy water and a headwind, it tends towards what one swimmer called ‘messy, brutal and brilliant’. 

In 2021 the Hurly Burly is at the start of the open water season, which means swim participants need: 

  1. Fitness: to be able to swim at least 7km confidently without tidal assistance. 
  2. Pace: swimmers need to be in the 37 minute mile band (measured as the time it takes you to swim a mile of relaxed continuous front crawl in a pool, without big push-offs). In a 25 m pool a mile is 64 lengths. Pace is important, to reach the finish before the tide turns. 
  3. Cold acclimatisation: the water is likely to be 12-14 degrees, and wind chill could chill you further. Dipping over winter may help cold resilience, but it is also possible to be ready starting in April/May.
  4. Open water/ outdoor swim experience: the first stretch of the swim is exposed, and there may be chop, rain or a headwind. Exciting if you feel up to it, but worth being prepared!

Swimmers and runners should be ready for a bad weather day (choppy water or a headwind), and for cold temperatures in and out of the water – extra layers of neoprene for swimmers or a windproof layer for runners are suggested.

We recommend that run-swimmers can run 11k in around 1 hr 30 minutes, whilst run-only entrants have no time limit.


The Hurly Burly will take place on Saturday the 26th of June 2021. Registration will be open on Friday afternoon and early on the Saturday morning, to enable an early start for run-swimmers, runners, and swimmers. The swim briefing will take place at around 7am, with registration before 6.45am. (Run swimmers have an earlier start). 

Registration packs will be sent by post, but you will still need to leave time to register before your swim – detailed event timings will be shared with swimmers in the event information pack, around 2 months before the event. 



The 11K run takes place at the same time as the swim, so at some point in the course you will see swimmers in the estuary beside you. The route will take you from Barmouth Beach, over the iconic Barmouth bridge then flanks the estuary all the way to Penmaenpool. Perfect for supporters who might not be water lovers but would like to get in on the action.


A 11K run followed by the 10K swim for those of you keen for a double challenge. You will be bused to Penmaenpool to join the Mawdacch Trail, run 11k to the swim start in Barmouth alongside the banks of the estuary and across the Barmouth Bridge, then swim back under it with the other swimmers on the incoming tide. This is a long run before a long swim: you can run in your running clothes, change and have a drink before setting off with the other swimmers (there will be a small time gap between the two events giving time for this to happen, and swimmers to depart together).

A long run before a long swim requires good nutrition. The founder of, Mike Alexander, offers advice in ‘Survive’ so you don’t let running cramp your style. Please read!

Jess Rose
Jess Rose
Jess Rose
Jess Rose


We have worked with a remarkable professional water safety team for over 10 years, who deliver the best water safety and support at all our events. Swimmers are flanked by professionally qualified employed lifeguards throughout the swim. There is no feeding station – instead swimmers are advised to tuck sustenance into their wetsuit, such as an energy gel.  Lifeguards will also carry emergency supplies. 


We welcome skins and suits swimmers at our events, but Skin Swimmer Passes must be applied for and are not guaranteed. All tickets are sold on the basis that participants will wear full length swimming wetsuits or full length sleeveless wetsuit. 

WETSUITS: Your wetsuit must, at least, cover you from shoulders to below the knee, be made of neoprene and be designed for swimming / triathlon / swim-run (i.e. not scuba diving or surfing).Surf wetsuits do not offer the same mobility or buoyancy balance as swim wetsuits, which leads to physical issues completing longer swims. 

SKIN SWIMMER PASS: Skin Swimmers Passes are awarded on the basis of suitable experience and must be applied for by the 18th April 2021 using this form. Once granted, the pass is valid for all 2021 OSS events. Applications are vetted by the Events Managers and decisions are non-negotiable. If you filled in the skins swimmer application prior to 2020 events we ask that you fill it in again to provide your most up to date experience. 

Swimmers who completed a 2019 event with The Outdoor Swimming Society in skins will automatically be granted a 2021 Skins Swimmer Pass. 

If you are fairly new to skins swimming, but think you’ll want to swim the event in without a wetsuit please fill in the Skins Swimmer Pass application form nearer to the deadline so you can provide the experience you have had to date, rather than what you expect to do.  If you don’t get a pass and don’t want to swim in a wetsuit you can transfer your ticket to a friend. Cut off for ticket transfers for the Hurly Burly is 25th April 2021, one week after the Skins Swimmer Pass application deadline. 

Vivienne Rickman Poole


Most people swim our events using front crawl, but we do have swimmers that do butterfly and breaststroke. Breaststroke is not generally recommended because it’s hard on the knees to swim this distance in a wetsuit. If you are planning to do this swim fly, please let us know – We would love to follow your journey!


We welcome and can aim to accommodate all swimmers with additional needs who would like to swim as much as we can. It is essential that those with additional needs, or anyone who has concerns about their ability to take part in this event, seek their doctor’s advice before taking part, and please contact us email the event manager prior to buying a ticket or as soon as possible once you have a ticket, to discuss how we can accommodate you. Swimmers with additional needs will be accommodated within the existing water safety provision wherever reasonable adjustments are possible (no separate arrangements can be made), and will need to attend an additional safety briefing prior to the swim.


Events run by The Outdoor Swimming Society are tow-float free. We have ample safety cover who watch swimmers via their brightly coloured hats. Tow floats makes sighting swimmers more difficult by doubling the number of brightly coloured objects in the water, and may entangle other swimmers. It is sometimes stated that tow floats make retrieving an unconscious swimmer easier, however tow floats are not tested or rated to act as a safety device in this way. Snorkels and fins are not permitted as the hard edges risk injuring other swimmers at the swim start in particular.

Most swimmers with personal medication tuck it up the sleeve of their wetsuit – however, if this doesn’t cover your needs and you want to use a tow float for this purpose please contact the event manager.


All swimmers and their supporters will park in Barmouth (car parking charges apply).  Spectators can then take a coach (prebooked tickets only) to the finish village to meet their swimmers and runners, at the George III Pub, Penmaenpool, where there will be good food, fire pits and hot tubs for all to enjoy. Spectators and entrants (a free coach transfer to Barmouth is included in event tickets) can then make their way back to Barmouth. 

Please note, there is NO PARKING at the event finish. There is very limited disabled parking at the event finish, but it is not possible for event traffic other than these permit holders to park anywhere near the event finish – if you need a disabled car pass please contact us

Jess Rose


Our events are run, on land, by a small but fantastic army of volunteers. If you or your supporters would like to join the #OSSteam for event day or a day around the event, please read this Hurly Burly volunteering factsheet. #OSSteam members will receive a free top, free parking during the event, a discount on a future swim entry and Hurly Burly 2021 event merchandise, early-bird access to 2022 tickets for all OSS events, and a whole lot of love from The Outdoor Swimming Society Events team and swimmers as they make this swim possible for others.

Jess Rose


The 2020 Hurly Burly was cancelled in 2020, with all participants offered a full refund or a rollover to 2021. Information on this cancellation can be found here. A further update on the Hurly Burly 2021 date, sent to all 2020 entrants, can be found here.  If you have a Seasonaires ticket (a ticket for all 2020 events) our update can be found here.

All 2020 tickets for the Hurly Burly have automatically been carried over to the 2021 event, unless a refund was applied for. The refund window is now closed, but the free transfer window is open until 31st October 2020 – the recipient of a ticket transfer can confirm the transfer here. The ticket transfer window will reopen in the 1st December 2020, if tickets sell out, until the 25th April 2021, with ticket transfers incurring a £20 admin fee.


We will do everything we can to run the 2021 events. As part of event preparation for 2021 our event team will undertake planning of all aspects of the event to make sure they are Covid-19 secure and can meet changing circumstances.

We will communicate all information to you by email: this year more than any, please save to your address book to ensure you receive and read event communications. An Event Information Pack will be issued to all participants 2 months prior to the event and will include any special measures we are taking.

Please be aware we can only run events if all WHO and UK Government guidelines in place at the time of the event can be met, and the event is supported by local councils and event stakeholders. If the event is unable to run due to a local lockdown or change in national or local circumstances due to Covid-19, we will do our best to provide a suitable alternative to the event (at a different venue or on a different weekend), but this may not be possible. One foreseeable scenario is that we have to restrict spectators to reduce social transmission, increase the ability to physically distance entrants, and to enable effective tracking and tracing. We advise you to check the terms and conditions of associated bookings such as accommodation and travel so you are fully aware of their cancellation policy if changes to the event do happen.

Whatever changes are introduced, we hope to deliver the same feel-good events as ever.



After the statutory 14 day cooling off period, tickets cannot be refunded or deferred. 

If you know you will not be able to attend the event:

We realise that situations change and you might get injured, change jobs, or get invited to your best friend’s wedding. As your entry is NON refundable we suggest you consider taking out insurance to cover any costs you incur if you are not able to attend the event. Please check the conditions of your policy carefully to make sure it provides the cover you require.

You may be able to transfer your ticket to another swimmer. The free transfer window is open now and will run until midnight on the 31st October 2020. The second ticket transfer window will open again on the 1st December 2020, on the condition that tickets for the event have sold out, and stay open until the 25th May 2021.  Transfers in the second transfer window will incur a £20 admin fee. If tickets do not sell out, transfers in the second transfer window will not be offered.

You will need to find a recipient for your ticket (we recommend advertising you ticket on the Hurly Burly event Facebook page) and you will need to arrange for the transfer of payment for the ticket between yourselves. You are responsible for making sure the recipient is aware of all of the terms of the ticket, including any fundraising or volunteer commitments included within the ticket. 

The recipient of the transfer should visit the Hurly Burly ticket page and select “Hurly Burly 2021 ticket transfer”. After the 16th August 2020, your ticket is yours to keep and no transfers are possible. 

If the event is cancelled by The Outdoor Swimming Society:

No refunds are given if we have to cancel or curtail the event due to adverse weather, pollution, government orders or other factors outside of our control.

The OSS has a robust attitude to both safety and risk and works with an extremely professional water safety crew to ensure that the event will run if it is safe to do so. In the unlikely event we have to cancel on the event day or immediately before the event due to, for example, storms, lightning, or heavy rain that impedes the view of the safety team then you will not be offered a refund or a deferred entry to the next year’s event. At this point, everything will be in place for the event to take place and most, if not all, event expenses will have been incurred.

The OSS does not hold cancellation insurance to cover this eventuality as insurance of this nature is extremely expensive and would not cover all costs incurred by the event. 

Please see our Event Terms and Conditions for more information. 

Jess Rose


Swimmers are free to raise money for any charity (or none), and we are delighted to partner with Level Water once again as our primary event partner charity.

Level Water is a young and fast growing charity whose fortunes were changed overnight by involvement in the Dart 10k. The charity provides one-to-one swimming lessons for disabled children across the country, teaching them the basics then help them to join mainstream lessons and competitive clubs.

To help support its work, The Outdoor Swimming Society receives funds from sales of tickets for branded OSS events and merchandise. Every purchase you make supports the running of the society, which is a not-for-profit organisation in it’s self defined role as the UK’s (and the world’s)  best inspirer and informer on the art and sport of swimming.

Thank you for the continued support of our 2020 sponsors:


Thank you for the continued support of our supporters: Gwynedd County Council, Merioneth Yacht Club, Snowdonia National Park, the staff at the George III Hotel and Barmouth Leisure Centre, Barry and Susan Brightmore, Richard and Pat Owen, Gail Hall and local residents and businesses in and around Barmouth and Penmaenpool.