Swaddle UP Original, 1.0 Tog

The arms-up design is the whole point of this swaddle, and it's a genuinely different experience to a wrap-style swaddle - instead of pinning arms down, it holds them up and forward so a newborn can find a hand or fist to self-soothe with, which tends to translate into fewer startle-reflex wake-ups and longer stretches of sleep. The zip-free, snug inner pouch gives a closer fit through the body than most swaddles, while the outer two-way zip means night changes don't require a full unwrap and rewrap.

This isn't really competing head-to-head with the Grobag sleep bag so much as covering a different, earlier stage - the Swaddle UP owns the newborn window where arms-up comfort matters most, while the Grobag is the safer choice once your baby shows any sign of rolling, since a swaddle restricts the arms a rolling baby needs to right themselves. Most parents we'd point to this product end up buying both in sequence rather than choosing one over the other.

A strong pick for newborns who resist a traditional wrap swaddle or who seem to want their hands near their face to settle. Less suited to babies who show early rolling signs, or for parents who want one product to last from birth through toddlerhood - for that, the Grobag's longevity is the better investment.

It only has a short usable window - once your baby starts attempting to roll (often by 3-4 months), swaddling with arms restricted becomes a safety concern and you'll need to transition to a sleep bag, so budget for buying both products rather than one. It also runs slightly small and new parents often find it fiddly to fit around a wriggling newborn for the first few attempts before getting the technique down.