Published 15 September 2026
We modelled eight prints on a child at depth, in a pool and in British open water. The most common colour in children's swimwear turned out to be close to invisible.
Swimwear colour is not a safety device. It does not prevent drowning, it does not replace supervision, and no colour makes a child safe in water.
What a high-visibility colour does is narrower and worth having: it shortens the time it takes an adult who is already looking to find a child under the surface. That is the whole claim. Anything more than that is being sold something.
We were choosing prints for a first range and wanted to know how they would read in water rather than on a screen. The answer changed which prints we shortlisted, and it contradicted what most children's swimwear is actually made in.
Water does not dim colours evenly. It absorbs red wavelengths fastest, then orange and yellow, leaving blue-green light to travel furthest. At the same time the water column itself adds a veil of its own colour over everything behind it. So a garment at depth is not simply a darker version of itself — it shifts hue, loses contrast against the water, and can end up the same colour as the background it needs to stand out from.
Three things, in order of how much they matter.
It is the colour of the water, the colour of most pool floors, and the colour a very large share of children's swimwear is made in. In our pool model the blue-ground print turned the same blue-grey as the water around it; in open water it went dark teal and the pattern stopped reading altogether.
Cream, pale pink, washed-out pastels — these read as sunlight, foam and the pale floor of a pool. A print that was 41% pale ended up harder to pick out than a much darker one, because the pale areas merged into the bright background rather than the dark one.
They stay distinct against both a pale pool floor and dark open water, which is the property that matters — a colour that only works against one background is not much use when you do not get to choose the background.
Share of each print's area falling into colours that read well under water, against colours that disappear into it.
| Reads well | Disappears | |
|---|---|---|
| Pink & orange stripe | 70% | 30% |
| Bauhaus | 36% | 25% |
| Playground | 18% | 19% |
| Retro beads | 18% | 27% |
| Medallion | 19% | 38% |
| Zebra | 41% | 58% |
| Abstract shapes | 27% | 59% |
| Floral & moon | 10% | 88% |
The zebra is the interesting one. Its hot pink is excellent and does real work — but it is carried on a turquoise close to pool-water colour, so more than half the garment vanishes and the pink is left doing the job alone.
You do not need any of this modelling to check a swimsuit sitting in a drawer.
The most useful thing we can tell you: if a child is going in open water, a fluorescent colour beats everything here. Fluorescent dyes re-emit absorbed light, so they can appear brighter than the light falling on them — a different mechanism from simply being a saturated colour, and one no ordinary print can match. None of our prints are fluorescent. If visibility is your main concern, buy fluorescent, from whoever makes it.
We took the actual print artwork and applied standard light attenuation over a two-way path — surface down to the garment and back up — added the veiling light of the water column, converted to CIE Lab and measured colour difference against the background a searcher would be looking against. Two scenarios: a clear pool with a pale floor at 1.5 m, and silty green open water at 1 m.
This is a model, not a pool test. Real water varies enormously with silt, season, weather and light. The attenuation coefficients are illustrative values for two water types, not measurements of any particular place.
It also cannot represent fluorescence at all, which understates how much better a true neon would be than anything shown here. And print scale is not modelled: a large bold motif stays identifiable as it degrades, a fine one turns to mush sooner.
The underlying finding is not ours and we would not want it read that way. That fluorescent pink, orange and green read best under water — and that blue and white are the worst — is well established in drowning-prevention research. What we added was running our own prints through it and publishing the result, including the ones that came out badly.
We kept the blue floral. It is a genuinely lovely print and plenty of brands sell blue swimwear — but it will not be the hero, and it will not be the only option in a size.
The pink and orange stripe moved up our list. And the quiet sea-green ticking we were most pleased with turns out to be close to camouflage in British water, which is a irritating thing to learn about your own favourite and the reason we are reconsidering its ground colour.
We are making single-layer swim shorts for children, launching in 2027. There's a list if you want to be told when they exist.