IKEA UNDERLIG Foam mattress for junior bed

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Images: IKEA. Shown size and configuration may vary.

IKEA

UNDERLIG Foam mattress for junior bed

Name: IKEA UNDERLIG Foam mattress for junior bed
Brand: IKEA

Best for: Toddler/junior bed mattress

A 3⅞″ foam mattress for IKEA's 27½″ × 63″ junior beds, with two comfort sides.

Good to know: Junior size only fits junior beds of that size.

Type: Foam
Height: 3.875″
Sizes: 1 ready-made

Your size

27½ × 63 in · 3.875″ tall

Where to get it

ikea.comOrder online · delivered to you See price
Kids and cribMade for kids See the list

Returns: No sleep trial as such: IKEA US lets you exchange a mattress for another mattress once within 90 days; opened products can be returned within 180 days with proof of purchase (unopened within 365 days), but not if dirty, stained or damaged Details

We may earn a commission if you buy. Check the price for your exact size and height on the seller’s site.

The short version

Worth a look if

Toddler/junior bed mattress

Good

A 3⅞″ foam mattress for IKEA's 27½″ × 63″ junior beds, with two comfort sides.
2 firmness choices: Medium firm (egg-shaped side), Firmer (smooth side)
Trial: No sleep trial as such: IKEA US lets you exchange a mattress for another mattress once within 90 days; opened products can be returned within 180 days with proof of purchase (unopened within 365 days), but not if dirty, stained or damaged
Buyers called it very comfortable and liked that the cover comes off.

Think about

Junior size only fits junior beds of that size.

Based on the maker’s published specs and terms, and the owner reviews linked below. We haven’t slept on it. Something wrong? Tell us.

What owners say

From reviews on the seller’s site A small set of real reviews, each linked to its source. Not a star rating.

Only IKEA-hosted reviews were found, and few are written: buyers call it comfortable and like the removable cover.

What people liked

Buyers called it very comfortable and liked that the cover comes off. Source ↗

What to weigh up

No substantive concern verified in this small sample. This is a gap in the evidence, not proof of no drawbacks.

Sources & sample limits

Written reviews shown on IKEA's own US product page (brand-hosted; not counted) Sample: 0 owner reports.

Only IKEA-hosted reviews were found, and only the reviews visible on the page were read. No Reddit or forum owner posts naming this model were found in this pass.

Research checked October 14, 2026. These are sourced observations, not our own product tests or a star rating.

Every size it comes in

Junior27½ × 63 inAs listed

Taken from the maker’s size options, in the inches it publishes. Tap a size to compare every mattress made in it. Sizes marked “as listed” don’t exactly match a standard size, so check your frame.

Price for every size

From the maker’s site on Oct 24, 2026. Prices change often, so check before you buy.

Size	Inches	Price
Junior	27.5 × 63	$99	See it

How it compares

Beside the most similar mattresses from other brands.

	UNDERLIG Foam mattress for junior bedIKEA	The Grand RoyaleAlaskan King Bed Company	The OriginalAlaskan King Bed Company	The RoyaleAlaskan King Bed Company
Type	Foam	Foam	Foam	Foam
Queen price	—	$11,000	$3,800	$4,400
Height	3.875″	15″	11″	12″
Trial	See terms	See terms	See terms	See terms
Odd sizes	None	1	1	1
Expert reviews	None yet	None yet	None yet	None yet

What’s inside

1Polyester cover (removable, washable at 140°F)
2Polyurethane foam (1.7 lb/cu.ft.), egg-shaped side and smooth side

Feel: Medium firm (egg-shaped side), Firmer (smooth side)
Height: 3.875″
Custom sizes: Not offered for this model

Returns and ordering

Trial and returns

No sleep trial as such: IKEA US lets you exchange a mattress for another mattress once within 90 days; opened products can be returned within 180 days with proof of purchase (unopened within 365 days), but not if dirty, stained or damaged

Before you order

Measure inside the frame, not the old mattress
Check clearance above for the height you pick
Make sure your base supports it
Buy sheets in the same exact size

Questions

What is it made of?

3⅞″ two-sided foam junior-bed mattress, 27½″ × 63″: egg-crate medium-firm side and smooth firmer side, hot-washable cover.

How firm is it?

Medium firm (egg-shaped side), Firmer (smooth side) That’s the maker’s description; we haven’t measured it.

Which sizes and heights can I get?

1 sizes, 3.875″. See every size. Confirm your exact size and height with the seller.

Are the reviews about this exact mattress?

From reviews on the seller’s site. Only IKEA-hosted reviews were found, and only the reviews visible on the page were read. No Reddit or forum owner posts naming this model were found in this pass.

Where did this information come from?

Checked 2026-10-17. Specs and terms can change.