Mattress Online HydroShield Comfort King Size Mattress
The HydroShield Comfort is Mattress Online's own-brand foam mattress, available in UK Single, Double and King sizes.
- Water-resistant cover for kids' rooms
- Reflex foam top eases pressure
- 100-night trial & 10-year guarantee
£295
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Mattress Online HydroShield Comfort Mattress
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Mattress details
Mattress
Mattress Online HydroShield Comfort Mattress
Size
Firmness
Medium Firm
Construction
Foam
Eco-Friendly
Depth (cm)
14
Layers
2
Layer Details
Ecofoam
A 10cm layer made from 100% recycled foam, which means the bulk of the mattress does the supportive work while keeping materials out of landfill. It gives the mattress its medium to firm character.
Reflex Foam
A 4cm layer of Reflex foam sits above, adding pressure-relieving comfort where your body meets the mattress. It also adds durability, helpful in a single-sided design you can't flip.
Layer details from mattressonline.co.uk product page, September 2026.
Key benefits
- 75cm of width each: Two people sharing get 75cm each, which means you can both change position in the night without landing on someone else.
- Extra length for taller sleepers: At 200cm the UK king is 10cm longer than the UK double, a difference tall sleepers feel at the footboard rather than in theory.
- Room to prop and shift: During pregnancy or recovery from surgery, when pillows multiply and positions change hourly, the extra width means your partner isn't squeezed to the edge.
- Space on different schedules: If one of you gets up hours before the other, that 75cm each gives the early riser room to slip out without a scramble across shared territory.
- A budget-friendly route to king size: The HydroShield Comfort's recycled Ecofoam build keeps this an affordable way into the UK's most popular upgrade size; compare the retailers listed on this page for current prices.
This size suits you if...
You share the bed every night and a double has started to feel cramped, especially if one of you tosses, gets up early or takes a dog's worth of extra space. It also suits couples where one partner is approaching six foot, since the 200cm length adds 10cm over a UK double. Allow at least 2.7m x 2.9m of bedroom space.
Consider another size if...
Your bedroom is below the 2.7m x 2.9m we suggest, which is common in new build masters once the wardrobes go in. We'd recommend the UK double instead, which needs at least 2.6m x 2.8m.
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FAQ's
Is the HydroShield Comfort worth getting in a UK king instead of a double?
For couples, usually yes. The UK king is 15cm wider and 10cm longer than the UK double, which works out at 7.5cm more width each. That's the difference between sharing comfortably and sleeping in formation. If you sleep alone, the UK double is the more sensible buy for this mattress.
What room size does the HydroShield Comfort UK king need?
We suggest a bedroom of at least 2.7m x 2.9m for a UK king, which leaves room to walk round the bed and open drawers. Measure with wardrobes and bedside tables in place, since a new build master can feel smaller than the floor plan suggests. Anything tighter and the UK double fits better.
How big is the HydroShield Comfort in a UK king?
It measures 150 x 200cm, which is 5ft x 6ft 6in. Two people sharing get 75cm of width each. The mattress itself is 14cm deep in every size, so bear that in mind when buying fitted sheets for a king.
Is the UK king HydroShield Comfort long enough for a tall sleeper?
At 200cm it's 10cm longer than the UK double, so anyone around the six foot mark gains genuine toe room. If length is your main reason for upgrading, the UK king is the size to pick here, since the UK double and UK single are both 190cm long.
Does the HydroShield Comfort come in a size bigger than a UK king?
No, the UK king is the largest size this mattress is made in. If you want the 90cm each that a UK super king offers, you'd need a different mattress. For most couples upgrading from a double, the UK king's 75cm each is a noticeable step up on its own.