King Mattresses

A king size mattress gives you room to stretch out like you are in a hotel, even when you share the bed every night. This collection of king size mattresses suits Aussie bedrooms of all shapes, from compact main rooms to large suites where the bed is the star of the space. You get a mix of contouring foam comfort, pressure relief for side and back sleepers, and steady edge support so every part of the king mattress size feels usable. Match your king bed mattress with Koala bedding and bedroom furniture for a sleep zone that looks calm and feels seriously comfy.

 
Clear all
  • Save 30%
    Luxe comfort
    Modern bedroom with a beige upholstered bed, featuring a Koala mattress and assorted pillows. Minimalist decor on grey walls and wooden side table.
    Mattress infographic on dark green background detailing a seven-zone support core for head to feet; emphasises contouring to body curves.
    Koala Luxe Mattress
    Close-up of a white mattress with a dark green trim and a "koala" label. It rests on a textured bed frame. A blurred background features a tan object.

    Koala Luxe Mattress

    (897 reviews)

    Koala Luxe Mattress

    Ultimate luxury comfort & support

    King • 4 Sizes
    Save $837
    $1,953
    $2,790 $1,953
    Sale
  • Save 30%
    Premium comfort
    Modern bedroom with a thick mattress on a wooden bed frame. Light grey walls, a stone side table, white lamp, and green decor accents.
    Mattress with advanced ergonomic support, featuring a white and grey five-zone design for tailored body contouring.
    Koala Plus Mattress
    Close-up of a grey Koala mattress on a wooden bed frame. The mattress features branding, certification logos, and a detailed fabric pattern.

    Koala Plus Mattress

    (1504 reviews)

    Koala Plus Mattress

    Advanced cooling & pressure relief

    King • 6 Sizes
    Save $597
    $1,393
    $1,990 $1,393
    Sale
  • Save 30%
    Classic comfort
    Modern bedroom with a wooden bed frame, light green mattress, and neutral bedding. Artworks and decor on white walls, and a side table.
    Mattress with essential ergonomic support features, highlighting three zones: shoulders, hips, and legs. Text on muted green background.
    Koala Mattress
    Koala Mattress

    Koala Mattress

    (2952 reviews)

    Koala Mattress

    Bestseller for comfort & support

    King • 5 Sizes
    Save $447
    $1,043
    $1,490 $1,043
    Sale
  • Save 30%
    Best seller
    Koala OG Mattress
    Koala OG Mattress
    Koala OG Mattress
    Koala OG Mattress

    Koala OG Mattress

    (27949 reviews)

    Koala OG Mattress

    Support where you need it

    King • 5 Sizes
    Save $357
    $833
    $1,190 $833
    Sale

Shop Mattresses by Size

Shop King Mattresses

Shop King Size Mattresses For Bigger, Better Sleep

King Mattress Size Comfort For Every Sleeper

King size mattresses in this range focus on that balance between soft comfort and proper support. A King Size Mattress from Koala combines Kloudcell-style foam, zoned support and motion isolation so restless sleepers are less likely to wake their partner. Many people type in searches like best king size mattress for side sleepers with back pain, and this layout speaks directly to that need, with shoulder and hip cushioning that still holds your spine in a better line. Looking for a king size mattress that feels roomy, keeps the bed stable and helps you wake up less sore?

King Size Mattresses Made For Real Aussie Bedrooms

A modern king size mattress from Koala fits real homes, not just showroom layouts. The king bed mattress arrives in easy-to-handle boxes and is simple to move through lifts and tight hallways, then pops out to full size on your existing bed frame or base. Breathable foam, airflow channels and cool-to-touch fabrics help hot sleepers through sticky summer nights, and a medium-firm feel suits a mix of sleeping positions. This way, your king size mattresses work for couples with different sleep habits, tall sleepers who need more leg room and anyone who wants that hotel-style feel at home.

Shop similar collections: Mattresses | Queen Mattresses | Super King Mattresses | King Bed Bases | Bedding

King Bed Mattresses Backed By Koala Care

Koala king bed mattresses come with fast delivery, a 120-night trial and long warranties, so you can test the feel in your own room with plenty of time to decide. Koala uses thoughtfully chosen foams, low-VOC glues and timber from responsible sources across its range, so your king size mattress plays a part in a more planet-friendly bedroom. One short brand truth sits behind the whole collection: Koala wants Aussies to sleep better on products that feel good to live with and good to buy. From the first unboxing to years of use, these king size mattresses are built for easy setup, comfy nights and a bedroom that still works if you move, rearrange or refresh your style.

Green delivery van with "koala" branding parked in a driveway. A person unloads a large brown box from the van. Lush greenery surrounds the scene.

Free, same-day mattress delivery

Order by 3pm on weekdays and enjoy same-day delivery in metro areas. All mattresses are delivered for free Australia-wide.

No hidden fees—just fast, free delivery.

Find out more
  • Woman sleeping on a white mattress, covered with a white duvet. Behind, a wooden headboard, and framed artworks on the wall.

    Buy it, get it, try it

    Take up our 120 day trial to see if it's the right match for you.

  • Woman excitedly stands next to an assembled wooden bed frame. A large cardboard box labeled "koala" is on the floor. Minimalist room decor.

    Not for you? Return it.

    Contact our customer service team to return it. We'll refund you the full purchase price you paid for your Koala product(s).

  • Showroom of sofas and armchairs in light grey and blue, with "Koala Second Home" text overlay; furniture recovery and factory outlet.

    We re-use or recycle

    Returned products are sent to Koala Second Home, donated to charity, or recycled into carpet underlay.

FAQs about king mattresses

What are the dimensions of a king-size mattress, and will it fit in my bedroom?

A standard king mattress size is 203 cm wide by 203 cm long, providing extra space for couples or individuals who prefer enough room to stretch out. If you need to save on space, consider a queen-size bed mattress, slightly narrower but the same length. 

Before purchasing, it's essential to measure your bed frame to ensure the king mattress size fits perfectly.

Are Koala king mattresses suitable for adjustable bed frames?

We don't recommend using our mattresses on an adjustable bed base, as if the mattress is bent or folded for extended periods of time you may end up causing damage to the core and supportive layers, which would not be covered under our Koala Warranty.

Our mattresses have been engineered to work best on a flat platform or slatted surface that allows adequate ventilation underneath. If you need to buy a new base, check out our range of bed bases. They're super sturdy, no tools required and easy to assemble!

How do I care for and clean my king mattress?

We recommend spot-cleaning your king-size bed mattress with a mild detergent and a damp cloth for any stains or spills. Additionally, use a mattress protector to guard against allergens and moisture, extending the life of your mattress and maintaining its hygiene.