Best Soft Mattress Australia: What to Look for Before You Buy

Shopping for a soft mattress in Australia sounds simple until you start comparing options. "Soft" means different things to different brands. Ultra-soft mattresses that hug the body work brilliantly for some sleepers and cause back pain for others. And plenty of buyers start their search wanting a soft mattress and discover, after some careful reflection about their sleep style, that a balanced medium or medium-firm feel actually suits them better.

This guide walks through what a soft mattress actually is, who suits one, what to look for when buying, how soft compares to medium and medium-firm feels, and — importantly — when a soft mattress may not be the right choice. The goal is to help you decide with confidence rather than commit to a firmness that doesn't fit your sleep style.

The best soft mattress provides cushioning and pressure relief while maintaining enough support to keep your spine comfortably aligned. Side sleepers and lighter-weight sleepers often prefer a softer feel, while others may find a medium or medium-firm mattress offers a better balance of comfort and support. Match the firmness to your sleep position and body weight rather than assuming softer is always better — spine alignment matters more than surface softness alone, and pressure relief is available in medium-firm mattresses too.

Key takeaways

• "Soft" typically means 2–4 on the 1–10 firmness scale — plush, contouring, and hugged

• Side sleepers and lighter sleepers often benefit from softer feels; back sleepers, stomach sleepers, and heavier sleepers usually need medium-firm structural support

• A good soft mattress balances cushioning comfort layers with a firm support core — the soft feel comes from what's on top, not from sacrificing structural support

• Pressure relief is available across the firmness spectrum, not only in ultra-soft mattresses

• Koala mattresses are engineered for balanced comfort and support — the Koala Luxe is the plushest option in the range with 9cm Kloudcell® and 7 multi-layered support zones per the Luxe product page

What is a soft mattress?

Mattresses are typically rated on a 1–10 firmness scale where 1 is very soft and 10 is very firm. Soft usually means 2–4 on that scale. Plush is sometimes used interchangeably with soft, though it can also describe a soft top layer built over a firmer support core — often called plush-firm or pillow-top construction.

For the sleeper, "soft" translates to:

• Greater initial sinkage into the top comfort layer

• Body cradled by contouring foam or fabric

• Less "surface tension" and more "hugged" feel

• Pressure points at shoulder and hip cushioned rather than pushed against

Soft doesn't mean unsupportive. A well-made soft mattress still supports spine alignment — it just achieves that support through deeper contouring layers over a firm support core rather than through a firm surface. A truly unsupportive soft mattress sags too far and misaligns the spine, causing back pain over time.

Comfort vs support balance. The comfort layers provide the soft feel; the support core beneath keeps the spine aligned. Look for both — soft comfort and firm structural support. Cheap "soft" mattresses often skimp on the support core and rely on the comfort layer alone, which is why they sag within a few years.

Not everyone should sleep on a soft mattress. Body weight, sleep position, and existing back conditions all shape whether a soft mattress is the right choice. This guide walks through the factors that determine which firmness suits you specifically.

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Who should choose a soft mattress?

Some sleepers benefit meaningfully from a soft feel. Others don't.

A soft mattress often suits:

• Side sleepers. Pressure at the shoulder and hip is the biggest sleep-quality issue for side sleepers. A soft comfort layer cushions those pressure points and keeps the spine aligned by allowing the shoulder and hip to sink to their natural depth

• Lightweight sleepers. Sleepers under 65kg apply less pressure to the mattress surface, so they sink less into a soft mattress than heavier sleepers do. A soft feel that would sink a heavier sleeper's spine too far may still support a lighter sleeper properly

• Sleepers who feel their current mattress is "too firm." If you wake with shoulder or hip pain, a softer surface may help. Note: waking with lower back pain typically suggests the opposite — either a firmer mattress or a stronger support core is likely what you need

• Sleepers who prefer a "hugged" feel. Some people simply find the contouring, plush feel of a soft mattress more comfortable regardless of technical arguments about firmness

A soft mattress may not suit:

• Back sleepers. Back sleepers typically need balanced medium to medium-firm support to keep the lower back aligned. Too soft and the pelvis sinks below the shoulders, straining the lumbar spine

• Stomach sleepers. Firmness matters most for stomach sleepers — a soft mattress lets the hips sink below shoulder-line, causing lower back strain over time. Medium-firm to firm is typically the safer choice

• Heavier sleepers (over 100kg). Higher body weight compresses soft mattresses further, potentially reducing support. Heavier sleepers often benefit from medium-firm or firm mattresses that maintain structure under weight

• Couples with different firmness preferences. A single fixed firmness rarely suits both partners; consider a flippable mattress like the Koala Mattress (Core) with medium-firm and firm sides

Continue learning:

• Best Mattress for Combination Sleepers — position-forward guidance

• Best Mattress for Couples — couples with different firmness preferences

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What to look for when buying a soft mattress

Seven features separate a good soft mattress from a poor one.

1. Pressure relief. The core value driver for soft mattresses. Look for contouring comfort layers that cushion pressure points — memory foam, latex, or open-cell foams like Koala's Kloudcell® (proprietary open-cell foam, not memory foam).

2. Spinal support. A soft comfort layer needs a firm support core beneath it. Without that, the mattress sags into a hammock shape that misaligns the spine. Look for:

• Reinforced support core — a firmer foam base layer or pocket springs

• Zoning where relevant — targeted firmness at the lumbar region. Koala Luxe features 7 multi-layered support zones per the Luxe product page

3. Breathability. Soft mattresses trap heat more than firmer mattresses because you sink deeper into the surface. Look for:

• Open-cell foam construction — better airflow than traditional closed-cell memory foam

• Cooling technologies — cooling gel, phase-change materials, breathable covers

• Cover fabric — Tencel®, cotton, or performance blends that wick moisture

4. Motion isolation. Soft mattresses often deliver strong motion isolation because the contouring layers absorb movement rather than transferring it. This benefits couples. All-foam mattresses typically outperform hybrid mattresses for motion isolation.

5. Quality materials. Soft mattresses depend heavily on comfort layer quality. Cheap soft mattresses often sag and lose their contouring feel within 3–5 years. Look for:

• CertiPUR-US® certified foam — verifies foam quality without ozone-depleters, heavy metals, or high VOC emissions

• Higher-density comfort layers — resist compression over time

6. Sleep trial. More important for soft mattresses than for firmer ones because soft feel is highly preference-dependent. Look for 100+ nights (Koala offers 120).

7. Warranty. Soft mattresses are more prone to indentation and sag over time. A 10-year mattress warranty signals manufacturer confidence in construction durability.

Trust anchors that signal quality:

• ProductReview Mattress of the Year 2023, 2024, 2025 — Koala Mattress (Core) three-year streak

• CHOICE®-Recommended Koala SE

• CertiPUR-US® foam certification

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Soft vs medium vs medium-firm mattress

Direct comparison of the three most common firmness levels — with practical guidance for who suits each.

Soft (2–4): best for side sleepers and lighter sleepers who need pressure relief at shoulder and hip. Not typically the best choice for back or stomach sleepers, heavier sleepers, or people prone to back pain.

Medium (5–6): the middle ground that suits most sleepers. Combination sleepers often prefer medium because it adapts across positions. Many couples land on medium as the compromise.

Medium-firm (6–7): best for back and stomach sleepers, heavier sleepers, and people who prefer firmer structural feel. Still offers meaningful contouring for pressure relief.

Which firmness suits you depends on sleep position, body weight, existing back or joint conditions, and personal comfort preference. If you're unsure, medium or medium-firm is usually the safer default — pressure relief is still available, and the risk of spinal misalignment is lower.

Continue learning: Mattress Firmness Guide — full firmness reference.

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Is a soft mattress always better?

No. A soft mattress isn't universally better — it's the right softness for your sleep style that matters, not softness for its own sake. Some sleepers thrive on ultra-soft mattresses; others end up returning them after a month of back pain and irritation.

Advantages of soft mattresses:

• Pressure relief at shoulder and hip (side sleepers)

• Contouring "hugged" feel that many sleepers prefer

• Strong motion isolation for couples

• Suits lighter sleepers who don't sink too far

Trade-offs of soft mattresses:

• Can misalign the spine for back and stomach sleepers

• Heavier sleepers may sink too far, compressing the support core

• Higher heat retention due to deeper sinkage

• More prone to sagging over time — indentation shows up sooner than in firmer mattresses

• For sleepers already prone to lower back pain, a mattress that lets the pelvis sink below shoulder-line can worsen symptoms

Why the "best" firmness depends on the individual. Body weight, sleep position, existing sleep concerns, and personal preference all shape whether a soft mattress is right for you. If you have specific back or joint concerns, considering a physiotherapist's or GP's advice alongside firmness research is worthwhile — individual circumstances vary.

Pressure relief without ultra-softness. You don't need an ultra-soft mattress to get good pressure relief. Medium-firm mattresses with quality comfort layers — like the Koala Mattress (Core) on its softer flippable side, or the Koala Luxe with 9cm Kloudcell® and 7 multi-layered support zones (per the Luxe product page) — deliver meaningful pressure relief without sacrificing spine-aligning support.

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How to choose the right mattress for your sleeping style

Five factors determine the right firmness for you.

1. Sleeping position.

• Side sleepers → soft to medium-plush (pressure relief at shoulder and hip)

• Back sleepers → medium to medium-firm (lumbar support with mild contouring)

• Stomach sleepers → medium-firm to firm (keeps hips from sinking below shoulder-line)

• Combination sleepers → medium (adapts across positions)

2. Body weight.

• Under 65kg → can go softer; less sinkage overall

• 65–90kg → most firmness levels work; medium is a safe default

• 90–100kg → medium to medium-firm typically safer

• Over 100kg → medium-firm to firm; softer mattresses may compress too far

3. Comfort preference.

Comfort feel is subjective. If you're currently sleeping on a mattress you love, look for similar firmness. If you're moving away from a mattress you didn't love, note whether it felt too firm or too soft and adjust accordingly. Sleep trials of 100+ nights let you verify preference in your own bed.

4. Support needs.

Existing back pain, joint issues, or spinal conditions may steer the decision toward medium-firm regardless of position or weight preferences. Consider consulting a physiotherapist or GP if you have specific medical concerns.

5. Sleep issues to consider.

• Hot sleeping → prioritise cooling technology and breathable construction

• Partner disturbance → prioritise motion isolation (all-foam typically stronger than hybrid)

• Difficulty falling asleep → some sleepers benefit from the "hugged" feel of a softer mattress; others find it too enveloping

If your candid answer to these five factors leans toward balanced comfort and support rather than ultra-soft — as it does for most sleepers — a mattress engineered for that balance will serve you better than the softest option on the market.

Continue learning:

• How to Choose a Mattress — full buying process framework

• What Makes a Good Mattress? — quality feature definitions

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How the Koala range approaches soft-feel preferences

Koala mattresses are engineered for balanced comfort and support rather than an ultra-soft sleeping surface. Koala's proprietary Kloudcell® open-cell foam (not memory foam) is designed to combine pressure relief with structural support — the sweet spot between soft-feel comfort and spine-aligning firmness.

Firmness options across the Koala range:

• Koala SE — verified-quality entry-tier (CHOICE®-Recommended)

• Koala Mattress (Core) — flippable medium-firm / firm; three-year ProductReview Mattress of the Year winner. The softer flippable side gives buyers who want more contouring a middle-ground option without going ultra-soft

• Koala Plus — cooling-focused with Cooling Gel Kloudcell® + CoolThread™ (13% cooler than leading online brands per the Plus product page)

• Koala Luxe — the plushest option in the range. 9cm Kloudcell® top layer with 7 multi-layered support zones (per the Luxe product page), copper-infused layer, and Australian Cashmere blend cover. Best for buyers wanting a plusher feel with pressure relief

Who Koala's range suits:

• Buyers wanting balanced comfort and support — the majority of sleepers

• Side sleepers wanting quality pressure relief with structural support (Luxe specifically)

• Couples with different firmness preferences (Core flippable)

Who may want to look elsewhere:

Buyers specifically wanting an ultra-soft feel below 4 on the 1–10 firmness scale may prefer specialist plush-focused brands. Koala's range trends toward medium and medium-firm with the Luxe offering the plushest option — but not the softest option on the Australian market.

This transparency is deliberate. Rather than claiming Koala is "the softest," this article helps you determine whether balanced comfort and support is what you actually need — and if so, Koala's range is engineered to deliver it.

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Common mistakes when buying a soft mattress

The mistakes below turn up in returns and customer service tickets more than they should. Every one of them is avoidable at the buying stage.

Choosing the right mattress firmness isn't about finding the softest option — it's about finding the balance of cushioning and support that matches your sleep style, body weight, and preference. Side sleepers and lighter sleepers often benefit from softer feels; back sleepers, stomach sleepers, and heavier sleepers usually need medium-firm structural support. Pressure relief is available across the firmness spectrum, not just in ultra-soft mattresses. Use the sleep trial to verify what actually works for you rather than committing based on feel-in-store or online descriptions alone.

Find the right feel with Koala's mattress range

Rethinking whether a soft mattress is what you actually need? Many buyers start by looking for a soft mattress and discover they need a better balance of cushioning and support. Explore Koala's mattress range to compare comfort options across the SE, Core, Plus, and Luxe — including the plushest Luxe with 9cm Kloudcell® and 7 multi-layered support zones (per the Luxe product page).

Shop Koala Mattresses →

Still comparing mattress firmness? Read our Mattress Firmness Guide to understand the differences between soft, medium, and medium-firm mattresses before making your decision. To compare in person, visit our Koala Moore Park Showroom in Sydney.