How to keep a split king mattress together — pro tips and products

Image shows a Saatva Classic Split King Mattress on a beige fabric bedframe in a neutral colour bedroom
(Image credit: Saatva)

A split king mattress is perfect for couples and fans of the Scandinavian Sleep Method as they allow you to share a bed with your partner while sleeping on separate mattresses. However, how can you keep a split king mattress together and stop them from moving apart? As it turns out, a few clever accessories is all you need.

Most of this year's best mattresses for all sleepers and budgets are available as a split king. This mattress size can help with specific problems bed-sharing couples face, such as waking each other from sleep by tossing and turning in bed, or having very different mattress firmness preferences. However some couples may notice that their split king bed has a tendency to separate out over time. 

To prevent that from happening, here we show you how to keep your split king mattress together and the accessories you'll need. Plus, we've rounded up the best deals from this month's mattress sales on our top-rated split king mattress the Saatva Classic.

What is a split king mattress? 

A split king mattress is essentially two twin XL mattresses pushed together to form a king mattress, measuring at 76” x 80". This allows you both to have your own mattress, so you can customize your side of the bed without affecting your partner's.

A Saatva Split King Mattress inside a luxe hotel room

(Image credit: Saatva)

These beds are also great for anyone who shares a bed with a restless sleeper or someone who operates on a different sleep schedule to you, as it means their motions aren't transferred to your side of the bed. 

You can buy split king mattresses in a box that are compressed, rolled and shipped in a box to your door, as well as split king mattresses shipped flat and ready for sleeping on straight away.

Can you feel the gap in a split king mattress? 

You may be wondering if the gap in the middle of a split king bed (where the two mattresses meet) can be uncomfortable or annoying, but most sleepers can't feel or notice any gap. This is due to the twin XL mattresses being pushed very closely together, so there's little space between them. 

Close-up of a split king mattress dressed with white sheets and pillows

(Image credit: Getty Images)

Another major concern you may have is whether you can actually fall through the gap between the two mattresses if each party shifts around and forces the two mattresses apart. 

If this is a concern, you may want to consider joining the split king mattresses together so that they don't shift apart. Luckily, there are some ways you can stop your split king bed from separating, as follows...

How to keep a split king mattress together

1. Secure it with straps 

The first thing you may want to try is securing the legs of the two bed bases together by using connecting straps such as zip ties, velcro straps, and bungee cords. Some split king beds even come with their own connecting straps. Simply tie up where the two bed bases meet.

2. Fill the gap between both mattresses

FeelAtHome Twin to King Bed Converter Kit

(Image credit: Amazon)

This one can also help if you feel or notice the gap when sleeping. Use a bed bridge (also known as a gap filler or converter kit) to fill the gap between the two beds. This will not only create a smoother surface, but also connect the two mattresses together. 

3. Use non-slip pads underneath each bed

If your bedroom has hard flooring (such as hardwood or tiles) then it's easier for your bed to shift around. This is where non-slip pads or furniture coasters come in handy. These pads keep the bed's legs firmly in place by creating friction between the bed and the hard floor, so the bed won't shift apart when you move around on it. 

Our top split-king mattress and accessories

1. Saatva Classic Mattress Split King: was $2,990 now $2,542 at Saatva

1. Saatva Classic Mattress Split King: was $2,990 now $2,542 at Saatva
According to our testers for the Saatva Classic Mattress review, the Saatva Classic is one of the best hybrid mattresses on the market, and it's available in three firmness levels and two heights. A split king Saatva Classic mattress is now $2,542, saving you $448 in this month's Saatva mattress sale. You'll also get a year's trial, free mattress installation and a lifetime warranty.

2. FeelAtHome Twin to King Bed Converter Kit:was $48 now $39.99 at Amazon

2. FeelAtHome Twin to King Bed Converter Kit: was $48 now $39.99 at Amazon
This bed bridge boasts a four-star overall rating from over 5,000 reviews on Amazon. Made of foam, simply place the bed bridge between the gap and secure with the provided bed connector strap. Available in three different sizes, the 8" twin XL bed connector is now 17% off.

3. 3" X-PROTECTOR Non Slip Furniture Pads:was $12.91now $9.99 at Amazon

3. 3" X-PROTECTOR Non Slip Furniture Pads:was $12.91 now $9.99 at Amazon
These non-skid rubber pads come in a pack of 12 and have an impressive 4.6 overall star rating out of over 32,000 reviews on Amazon. User reviews were impressed with the pads stability, quality, and value, and you can now get a 3" 12-pack for under $10. 

Frances Daniels
Senior Sleep Staff Writer

Frances Daniels is a PPA-accredited journalist and Sleep Staff Writer at Tom's Guide with an MA in Magazine Journalism from Cardiff University. Her role includes covering mattress and sleep news and writing sleep product reviews and buyer's guides, including our Best Hybrid Mattress 2025 guide. She is hugely interested in the relationship between good sleep and overall health, interviewing a wide array of mattress and sleep experts to create well-informed articles about important topics such as nutrition, sleep disorders (from sleep apnea to night terrors), lucid dreaming, sleep hygiene, and mattress care. She is also our specialist on mattress toppers — producing mattress topper reviews and taking care of our Best Mattress Toppers 2025 guide — and takes the lead on all content related to fiberglass-free mattresses for a clean, non-toxic sleep. Outside of Tom's Guide, she has written for Ideal Home, Homes & Gardens, and Marie Claire. 

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