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Waterproof Packing List for Obstacle Racing

What an obstacle race does to gear that a trail run does not

The defining difference is that an obstacle race is designed to make you wet and dirty on purpose. A trail run tries to keep you dry; an event with 18 obstacles sends you through four water crossings, two mud pits and at least one dunk wall where you go fully under. That means every item you carry on the course will be submerged at least once, and everything you wear will be saturated by kilometre three.

The second difference is volume of contamination. Mud at these events is typically a silt and clay mix held in a pit that has been churned by thousands of feet, so it is fine-grained, abrasive and it holds water. A race vest worn through two mud pits carries 400 to 700 g of that mud on its own, and a pair of size 42 trail shoes picks up another 500 to 800 g. That is more than a kilogram of abrasive paste that has to go somewhere at the finish.

The third difference is what happens afterwards. You finish wet, cold and possibly bleeding from a scrape, and you have a drive home. Wind chill at 12 °C on soaked skin is genuinely dangerous, which is why the dry bag in this plan is not a convenience, it is the thing that gets you warm in the car park rather than shivering for forty minutes.

The two-bag system: dry bag and wet bag

Every experienced obstacle racer runs two bags and the split is absolute. The dry bag is a 10L roll-top holding a hoodie or a fleece, dry socks, a beanie, a towel, a bin bag for the car seat, and a phone and car key pouch. Nothing muddy touches it, ever, and it is not opened between the moment you pack it and the moment you are standing at the finish.

The wet bag is a 20L or 30L bag holding everything that comes off you: shoes, socks, race vest, shorts, gloves and any tape or strapping. It gets strapped shut at the finish and goes straight into the boot of the car. Using one large bag for both jobs is the most common packing mistake at these events, because the mud does not stay politely in one corner; it migrates through the whole bag within minutes.

The packing list with real volumes and weights

Pack for the finish, not for the start. You will wear the race kit to the start line and it will be soaked by the end, so the list below is almost entirely post-race kit. Weights are for dry items; shoes and clothing gain 300 to 700 g each once saturated.

The last row is the one people skip and then regret. Driving home in soaked trail shoes is cold, unsafe on the pedals and ruins the shoes. If the 10L will not take a spare pair, carry a pair of cheap sandals instead; they pack to 1.5 litres and 200 g. The first-aid kit sizing behind that 0.9 litre figure is set out in our first-aid bag guide.

Sizing: how much bag a race day actually needs

Work from the wet volume, because that is the number that surprises people. A saturated race kit of shoes, socks, shorts and a vest occupies 14 to 18 litres once it is stuffed in loosely, and it weighs 3 to 4.5 kg. Add a wet towel and a pair of gloves and you are at the top of a 20L bag. If the event includes a full wetsuit swim or a cold-water immersion, add another 4 litres.

The relay row is worth a moment. Four runners sharing one 40L wet bag is a false economy: each runner generates 3 kg of saturated kit and the bag will not close. Give every runner their own 20L or 30L wet bag and label them, then share one large 40L as an overflow for shoes. Bags that cannot close are not waterproof, and an overfilled roll-top is the single most common reason kit arrives home wet.

Waterproof ratings for dunk walls, mud pits and water carries

Obstacle racing is one of the few land-based activities that genuinely needs an immersion rating. A dunk wall puts your pack under 30 to 60 cm of water for the two or three seconds it takes to duck under, and a water carry with a bucket or a sandbag often means wading to chest depth. Neither is a long immersion, but both are real submersion events that a splash-proof bag will fail.

Note the last row: at most events the bag drop is a field, and after two hours of rain that field is a shallow puddle. An IPX7 bag will keep its contents dry while sitting in 2 cm of standing water, but the closure must be facing up. Roll the top, clip it, and stand the bag mouth-up; a bag lying on its side with the fold in the puddle is relying on one seal rather than gravity.

The rating language matters here because it is testable. The ISO and IEC frameworks define what immersion and jet testing actually involve, so a brand quoting a standard can be checked and a brand quoting adjectives cannot. Ask which test method sits behind any claim before you trust it with a car key and a phone.

Closing a bag with mud-caked hands

This is the practical skill that decides whether your dry bag stays dry. You cannot roll a closure with hands coated in clay silt, because the mud goes into the fold and the seal fails. The trick is to close the bag before you get muddy rather than after, and to build the race day around that sequence.

1. Pack the dry bag the night before, roll it three times and clip it while your hands are clean.
2. At the venue, do not open the dry bag at all until you have washed your hands.
3. Use the wash station first: most events have hose points near the finish.
4. Open the dry bag with clean wet hands, take what you need, close it immediately.
5. Load the wet bag last, strap it shut, and only then touch anything else.
6. Put both bags straight into the car boot and deal with them at home.

If there is no wash station, carry a 500 ml bottle of water in the dry bag purely for hand washing. It is 500 g of weight you never use unless you need it, and it is the difference between a sealed dry bag and a muddy one. Wet clean hands roll a closure perfectly well; muddy hands do not.

Shoes, socks and the post-race wet volume

Shoes are the awkward item. A pair of size 42 trail shoes saturated with mud weighs 900 g to 1.3 kg and will not compress, so two pairs dominate a wet bag. Carry them laced together by the laces so they hang as one unit rather than rolling around, and put each pair in a separate 5L bag inside the wet bag if you can spare the space; that keeps the worst of the grit off the clothing.

Socks deserve their own small pouch. A muddy sock inside a wet bag distributes silt across everything, and silt is what abrades film from the inside during the drive home. A 2L roll-top with four pairs of wet socks in it is a two-minute decision that saves twenty minutes of cleaning later. Blister care matters too: a macerated foot that stays wet for a three-hour drive is a foot that will not run for a week.

Electronics: phone, car key and timing chip

The phone and the car key are the two items that must not fail. Put them in a 2L roll-top inside the dry bag, giving two independent seals, and register them with the event so they can be matched to you if they are lost on the course. A timing chip is usually ankle-mounted and waterproof by design, so it needs nothing from your bag.

There is a second reason for the inner pouch: it is the only thing you need to find quickly at the finish. Standing wet and cold, you want one small bag you can grab without opening the main dry bag in the rain. Keep the pouch at the top of the dry bag, not buried under a hoodie, and keep a card and some cash in it too, because a phone with a flat battery or a cracked screen is common at these events.

Bag drop: labelling and finding your bag among eight hundred

A bag drop at a large event is a field with hundreds of near-identical black bags. Two things solve it: a distinctive colourway and a rigid tag. Choose a bag in a colour that fewer than one in twenty other runners will pick, and attach a tag with your race number written in permanent marker on both sides.

Colour coding also helps you use the system correctly under fatigue. Make the dry bag one colour and the wet bag another, and tell whoever is waiting at the finish which is which. The same principle is used by event teams ordering bags for a whole field, and our team and club guide covers how a colour split gets specified across an order.

Cleaning after the event: the drive-home sequence

Do not leave a wet bag closed in a hot car for two days. Silt plus warmth plus darkness is how a bag grows mildew that no amount of washing will fully remove, and the smell is permanent in a welded TPU shell. Deal with it the same evening, or at the very least open both bags and air them as soon as you get home.

1. Empty everything, hosing the mud off shoes and clothing before they go anywhere near a bag.
2. Rinse the wet bag inside and out with a hose at low pressure; never a pressure washer.
3. Work a thumb along the full width of the fold line to push out trapped silt.
4. Wash with lukewarm water and a mild soap; a soft brush on the weld corners only.
5. Rinse buckles through their full travel while wet to flush grit from the tongue.
6. Dry in shade with the mouth open, then store loosely rolled with the buckle unclipped.

A pressure washer is the one thing to avoid. It will strip a welded seam at 100 bar and it drives water and silt into the fold. A garden hose at normal pressure removes everything a bag needs removed. The full washing method, including what not to do with printed panels, is in our roll-top cleaning guide, and grit in hardware is covered separately in the buckle care notes.

What fails first on a race bag

Race bags fail in a predictable order, and knowing it tells you what to inspect. First is the fold line, because silt that was never rinsed out abrades the film every time the bag is rolled. Second is the weld corner at the base, where a loaded wet bag is dragged across gravel in a car park. Third is the buckle tongue, which takes grit and then gets forced by someone in a hurry.

Two of those five rows are entirely preventable with a two-minute rinse, which is why the cleaning sequence above is not optional detail. A race bag that is rinsed after every event and dried in shade will comfortably outlast the shoes it carries.

Race morning checklist

• Pack the dry bag the night before and roll it three times with clean hands.
• Put phone, key, card and cash in a 2L pouch at the top of the dry bag.
• Carry a 500 ml water bottle in the dry bag purely for hand washing.
• Colour-code the two bags and tag both with your race number.
• Pack a bin bag for the car seat and a pair of sandals or spare shoes.
• Check the wet bag is empty, unfolded and ready at the finish line.
• Stand both bags mouth-up at the bag drop, never on their side.

Run that list the evening before rather than on the morning, because a 06:00 start in a field with 800 other runners is not the moment to discover the dry bag is still full of last year’s kit. Everything on the list takes under ten minutes the night before and under thirty seconds each to check in the morning.

Event organisers and teams buying bags for a whole field work from the same list converted into a specification: volume, film thickness, seam type, hardware grade, colourway and the test data behind the waterproof claim. Compare it against the full product line before you fix a size.

Two risks sit outside what a bag can manage. Cuts and scrapes from obstacles are near-universal at these events and need proper cleaning rather than a wet wipe, and the CDC publishes wound-care and tetanus guidance worth reading before a first race. Hypothermia after a cold-water obstacle is the other, and the same source covers the signs. Abrasion and tear methods used to rate coated fabrics are standardised by ASTM. For wet events that last a weekend rather than a morning, see our festival camping guide.