Simba Hybrid Ultra Mattress Review UK 2026

A note from James, who has not slept on this yet

Lead tester · 86kg / 13st 8lb · hot sleeper · back/side combo · former Silentnight QC · not the 104kg tester

Quick verdict for UK buyers

Most expensive current Simba Hybrid. Tallest too. We mark it 4.2/5 on the specification — not 4.6, not 5 — because the spec is serious and the ticket, the 34cm practicality, and the diminishing returns versus Luxe and Pro are the missing points. That is not a night we slept. You are buying kapok, a max spring count, FusionCool, HeatRelease strips, PureLift, and hotel-climb height. You are not buying a different patent, and you are not buying a medical device.

Simba’s from-price was £1,749 for a single on 2 September 2026. Pro starts at £899. Luxe at £1,249. Those deltas are the review until we have a night. If you cannot name a reason you need 34cm and 7,300 Aerocoil — a genuine leftover hunger after Luxe, a taste for kapok loft, a bedroom that already lives at hotel height — buy the cheaper Simba that already solved the sleep and keep the difference.

Bottom line: flagship personality, 40cm-plus sheets already in the cupboard, two people on speed-dial, wait for a sale, use the 200 nights. Everyone else — look at Luxe or Pro and stop treating the tallest box as a personality. I am 86kg. I am not David at 104kg. I have not slept on this one.

Who the Hybrid Ultra is for

Should you buy the Hybrid Ultra?

The clever bit is a flagship tax

Kapok is the story Simba gets to tell only at the top. FusionCool is 250g of wool (80%), charcoal-infused bamboo (10%) and kapok (10%). HeatRelease graphite strips sit under that. PureLift mixes latex and coconut. Then you get the maximum Aerocoil count — up to 7,300 in three layers — on a 34cm stack. None of that is fake. None of it is a new kind of sleep if Luxe already hugged you. We have not had the Ultra night that would let me say otherwise.

A flagship tax is when the brand sells the last 10% of materials at 40% more money. You can count the extra springs on a spec sheet. You can still wake up and realise the night was the same shape as Luxe, only the bed is harder to sheet and harder to sit on. That is the risk. Comfort can be excellent. Value is the argument.

I will not pretend kapok is a medical fibre, or that 7,300 springs are a diagnosis. They are a very expensive way to stay inside a medium-firm brand’s plush end. If that sentence already feels like a relief, you do not want this model. You want Pro on a sale.

The 34cm climb: height, lift, sheets, personality

Flagship is a personality type, not a default upgrade. People who buy Ultra because it is the most expensive Simba are shopping a number. People who buy it because they already live at hotel height, already own 45cm sheets, and already have two adults in the house — those people are shopping a mattress. The difference is the whole page. None of this needs a fake bedroom diary.

Height. 34cm on a typical UK wooden frame or ottoman can put the sleeping surface well over 70cm off the floor. Fine if you like a platform hotel. Miserable if children scramble in, if your knees argue, or if you already raised the bed for drawers. Measure the frame, add 34cm, then stand next to a kitchen worktop (usually ~90cm) and be honest.

Lift. Simba’s Ultra page does not print a kilogram. It does say: due to the weight, take delivery into the chosen room, and keep children away from unboxing. Four carry handles are on the spec. Treat every 180° rotate as a planned manoeuvre. An ottoman lid with this on it is a piston test. Room-of-choice delivery is not a luxury on this height.

Sheets. Extra-deep is mandatory. 40cm pockets are the starting point; 45cm if you add a protector — and Simba wants a protector for the 10-year paperwork. The 35cm extra-deep sets that work on a 28cm Pro will ping off these corners. Budget the linen with the mattress. A free-bundle pillow does not put the corner back on.

Then who it suits by weight, based on the construction. Luxe already showed us the pattern: extra comfort layers that pocket Sarah Mitchell at 62kg / 9st 11lb can hammock David Patel at 104kg / 16st 5lb. Ultra is taller and plusher on the tile. That does not prove a hammock. It does mean height is not extra support. Match the kilogram nearest yours after you have been honest about the two-person lift. Then use the trial. We will update this review once we have slept on it.

What we do not know yet

This is the honest bit other flagship pages skip. We have not slept on the Hybrid Ultra. So we will not give you Sarah’s 2am quote, David’s sock-hop, or a cooling score from a terrace we did not run. Those sentences would be fiction.

• Feel at 62kg, 86kg and 104kg. Luxe already split the house. Ultra may do the same, harder. We will not score that until the mattress is in the room.
• Whether FusionCool or HeatRelease actually sleep cooler. Simba’s 4.4°C line is a lab figure on the upper foam, with strips versus without. Not a bedroom. Not our thermometer.
• Whether the night is better than Luxe. That is the only question that justifies another £500. We do not have it yet.
• A kilogram weight for the object. Simba does not print one on the Ultra page we checked.

If you buy before we update this review, you are the one running the trial — keep the 200-night paperwork.

What 34 centimetres and eleven layers actually are

Simba’s product tour numbers ten steps because some steps are pairs (two Simbatex pads, two of the three Aerocoil layers). The badge is still 11 layers | 34cm | up to 7,300 springs. Top to bottom, this is the stack on Simba’s UK spec, 2 September 2026. The bits that do not exist on Pro are the story. The bits that may barely change the night versus Luxe are the tax.

Spring arithmetic, because marketing loves a round number: two Aerocoil layers plus a third up to 2,500, SupportCore up to 1,000. That is the 7,300 story. You do not feel 7,300 as a count. You feel a very busy, very expensive hybrid. If you liked Luxe’s three Aerocoil layers at 5,700, you already know this family.

Firmness: plush on a medium-firm brand

Simba designs the Hybrid line to feel medium-firm. Ultra is the exception they actually print as plush on the product tile. The same page still says all Simba mattresses are meant to hug on top and hold underneath. We have not landed our own /10 because we have not slept on it, and a cutaway diagram will not tell you.

What we can say from the rest of the range: Luxe already felt plusher than Pro, and that extra travel was a gift at Sarah’s 62kg / 9st 11lb and a hammock risk at David’s 104kg / 16st 5lb. Ultra is the next step on the same ladder. Stomach sleepers who need a flat, firm surface are shopping the wrong end of Simba regardless. Use the 200 nights.

Sleep positions and body weight

This is a fit guide from the spec and from Luxe, not a panel we put on Ultra. Every “mixed” below means trial it. We will replace this when we have slept on it.

Body weight is not a vibe. It is how far you travel through the comfort layer before the core holds you. Sarah at 62kg / 9st 11lb often needs a softer top so her shoulder can drop. David at 104kg / 16st 5lb often needs that same top to stop sooner, or his hips make a hammock. James at 86kg / 13st 8lb sits between them — useful as a typical UK male, useless as a stand-in for a 104kg back sleeper. If you are shopping this Simba Hybrid Ultra because a review said “medium-firm,” match the kilogram figure nearest yours, not the brand icon.

Tester	Weight	Fit	What that weight actually did
Sarah Mitchell	62kg / 9st 11lb	Mixed	62kg / 9st 11lb, side. Luxe was her mattress. Ultra is plusher and taller on the tile — she may love the cloud or feel lost on loft she does not fully load. We have not put her on this model.
James Wright	86kg / 13st 8lb	Mixed	86kg / 13st 8lb, back/side, lead reviewer — not the 104kg tester. Slept on Hybrid, Pro and Luxe. Has not slept on Ultra. Would not climb from Luxe on a spec sheet alone.
Emma Thompson	71kg / 11st 2lb	Mixed	71kg / 11st 2lb, hot sleeper. More layers is more material. FusionCool and HeatRelease are Simba’s cooling story, not a night she has had on this model. Do not buy Ultra for a hang-tag °C.
Rachel Adams	68kg / 10st 10lb	Mixed	68kg / 10st 10lb, physio lens. No Ultra night. The veto we can already write is sheet depth and furniture: 34cm plus a protector is a 40–45cm pocket job. Alignment is a trial question.
David Patel	104kg / 16st 5lb	Mixed	104kg / 16st 5lb, back, sits on the edge. Luxe already over-sank his hips. Ultra is a taller plush stack. Height is not extra support. Trial first if you wanted max height because you are heavier.

Find yourself on the scale

Use these bands as a first filter, then use the trial. They are how this mattress behaved for our panel, not a medical chart. A 95kg side sleeper is not David, and a 70kg stomach sleeper is not Sarah.

Your weight	Fit on this mattress	Read this first
Under ~70kg, side	Mixed	Sarah’s band at 62kg. You may love the cloud, or you may feel lost on 34cm of loft you never fully load. Trial against Luxe, not a brochure.
~70–90kg, mixed or back	Mixed	James’s band at 86kg. The spec can be excellent. The climb, the sheets and the flagship tax are why he would not buy it from a cutaway. Emma Thompson at 71kg sits here too — cooling is unproven on this model.
~95–110kg, back	Mixed	David’s 104kg band. You will use more of the plush stack. That can feel luxurious. It can also be sink. Height is not extra support. Use the 200 nights.
Stomach, any listed weight	Skip	A plush flagship is the wrong choice here. Hips drop on a taller comfort stack. Start at Hybrid or Pro.
Hot sleeper buying layers for cooling	Poor	A 34cm stack is more material. FusionCool is a blend. HeatRelease is a lab strip. We have not slept on it. Do not buy Ultra for a hang-tag °C.

Manufacturer limit: Simba does not print a per-side kilogram limit on the Ultra page we checked. That is a warranty ceiling, not a comfort promise. David at 104kg is inside most UK boxed-hybrid caps and still the person most likely to find a plush surface too soft.

Couples with a large weight gap should read Sarah at 62kg and David at 104kg as the two ends of Luxe’s argument, then add 3cm. One mattress cannot run two firmnesses. Then add the practicality: two people to lift, 40–45cm sheets, a climb to sit. Use the trial as the product. We have not slept on Ultra. More on matching firmness to body type: firmness by sleep position.

UK buying details: trial, warranty, delivery

Rotate once a month for the first three months, then seasonally. Zip-off cover: 40°C, reduced spin, line dry. Do not bleach, tumble dry, iron or dry-clean. Single-sided — rotate, do not flip. Two people.

UK sizes and prices (2 September 2026)

Simba listed Hybrid Ultra from £1,749 including VAT for a single on the range tile when we checked. That from-price is the highest starting ticket in Simba’s current Hybrid line. A king was showing £2,599 on the product page the same day. A community-hero ticket on that king was £1,923.26 if you qualify. Prices move. Treat the table as a snapshot, not a promise. Do not pay a quiet full ticket.

Prices last checked 2 September 2026. Confirm centimetres if you have a continental frame. Shop bundles (pillows, protector, duvet) are promotions — not mattress layers. A free pillow does not make 34cm sheets appear in the airing cupboard.

Comparisons

If you want the whole UK range on one page — including which model we would actually buy — start on which Simba should I buy?

Hybrid Ultra vs Luxe vs Pro

Same trial, same guarantee, same Aerocoil family. You are shopping loft, height, and whether kapok is a personality. Pro is the Simba I would tell most people to order. Luxe is the step if Pro felt a bit short on sink. Ultra is for people who already know they want the tallest stack and will live with the climb. Full write-ups: Hybrid Pro review · Hybrid Luxe review.

Simba Hybrid Ultra FAQ