The Simba Hybrid Ultra is Simba's 34cm flagship with up to 7,300 springs and HeatRelease graphite, for hot sleepers wanting plush comfort.
The Simba Hybrid Ultra is Simba’s flagship: a 34cm, eleven-layer hybrid with up to 7,300 springs, a wool, bamboo and kapok comfort layer and HeatRelease graphite strips fitted as standard. Simba describes the feel as plush, which we place at 4 out of 10, and the regular price starts at £1,749 for a single.
The numbered specification on Simba’s UK product page lists eleven layers plus the graphite strips. Spring counts are for a king.
| Layer | Material | What it does |
|---|---|---|
| 1. Cover | 530g knitted polyester, Stratos treatment, zip-off top | Washable; 133g inner cover underneath |
| 2. FusionCool | 250g blend of 80% wool, 10% charcoal-infused bamboo, 10% kapok | Breathable, moisture-wicking top |
| Extra | HeatRelease strips: graphite, polypropylene, aluminium | Absorb excess body heat |
| 3 and 4. Comfort | Two layers of graphite Simbatex foam | Cushioning with airflow |
| 5 and 6. Microsprings | Two Aerocoil layers in 13 zones | Targeted support, low motion transfer |
| 7. PureLift | Latex and coconut fibre blend | Spring-like lift and elasticity |
| 8. Core | CertiPUR foam | Stability |
| 9. Support springs | Up to 2,500 high-carbon steel Aerocoil springs | Deep support layer |
| 10. Base springs | Up to 1,000 steel barrel springs | Edge support, less foam |
| 11. Base | CertiPUR foam, recycled-yarn cover | Foundation |
It carries more cooling hardware than any other Simba. The HeatRelease strips come fitted as standard, the FusionCool top layer blends wool with charcoal-infused bamboo and kapok, and both Simbatex foam layers are infused with graphite. Temperature matters for sleep quality: a review in the Journal of Physiological Anthropology (Okamoto-Mizuno and Mizuno, 2012) found that in real bedrooms, with bedding and nightwear in use, heat exposure increases wakefulness and reduces slow-wave and REM sleep. Simba’s figure for HeatRelease, up to 4.4°C lower in the upper foam layer under laboratory conditions, is a manufacturer claim and is worth reading as one.
Hot sleepers who want the plushest Simba and can justify the spend. Everyone else should compare it with the Hybrid Luxe, which has up to 5,700 springs against the Ultra’s 7,300 and the same steel SupportCore edge, for about 25% less in a double. The Ultra is sold in four sizes only, with no small double or continental sizes, and at 34cm it needs deep-pocket fitted sheets. Simba asks owners to rotate it once a month for the first three months and every three months after that. The top cover zips off for a 40°C wash, and the inner cover underneath can be slept on while it dries.
| Size | Dimensions (cm) | Regular price |
|---|---|---|
| Single | 90 x 190 | £1,749 |
| Double | 135 x 190 | £2,399 |
| King | 150 x 200 | £2,599 |
| Super king | 180 x 200 | £2,999 |
Regular prices at the time of writing (September 2026). Delivery is free to most of the UK, with room-of-choice delivery advised because of the weight, and the Ultra carries the standard 200-night trial and 10-year guarantee. All foams are certified to CertiPUR.
| Brand | Simba |
|---|---|
| Material | 530g knitted polyester cover with Stratos and zip-off top, FusionCool layer of 80% wool, 10% charcoal-infused bamboo and 10% kapok, HeatRelease graphite strips, two graphite Simbatex foam layers, two 13-zone Aerocoil microspring layers, a latex and coconut fibre layer, CertiPUR core foam, up to 2,500 steel Aerocoil springs, up to 1,000 barrel springs and a CertiPUR foam base. |
| Firmness | Medium soft (4/10) |
| Height | 34 cm |
| Sleep trial | 200 nights |
| Warranty | 10 years |
| Delivery | Free delivery to most of the UK |
| Available sizes | 90x190, 135x190, 150x200, 180x200 |
| Overall score | 8.4/10 |
| Certifications | CertiPUR |
“We recommend the Hybrid Ultra to hot sleepers who want the plushest Simba and can justify the spend, as it is the only model with HeatRelease built in, under a wool, bamboo and kapok top layer. If heat is not your main problem, the Hybrid Luxe keeps a steel edge with up to 5,700 springs, for about 25% less in a double.”
Also compared
The Simba Hybrid Pro is a 28cm wool-topped hybrid with up to 4,800 springs,…
Firmness: Medium firm · 200-night sleep trial
The Simba Hybrid is a 25cm medium-firm mattress pairing 1,900 Aerocoil microsprings with a…
Firmness: Medium firm · 200-night sleep trial
The Simba Hybrid Essential is a 20cm, four-layer hybrid with up to 1,000 Aerocoil…
Firmness: Medium firm · 200-night sleep trial
