Simmons Kids SlumberTime Naturally 4-Inch Mini Crib Mattress - Firm

Our review of the Simmons Kids SlumberTime Naturally 4-Inch Mini Crib Mattress finds it best for parents who need a simple, safe, and compact mattress for a mini or portable crib. The single biggest reason to buy is its firm, hypoallergenic fiber core that offers steady support for infants, combined with a naturally blended cotton cover and waterproof backing for easy cleanup. This mattress is designed specifically for mini and portable cribs at 38L x 24W x 4H, and it focuses on safety and low chemical emissions rather than luxury padding.

Key Features

• Compact fit: Measures 38L x 24W x 4H so it fits most mini and portable cribs without extra trimming or folding.
• Firm support: Hypoallergenic fiber core made from recycled bottles provides a consistently firm surface recommended for infant safety and spinal support.
• Waterproof cover: Naturally blended cotton cover with waterproof backing protects the core from spills and simplifies surface cleaning.
• Non-toxic construction: Built without harmful materials or chemicals so parents can feel confident about the mattress composition.
• Safety certifications: GREENGUARD Gold Certified and compliant with flammability, lead, phthalate and CPSIA testing to help reduce indoor chemical exposure.
• Made in the US: Domestic manufacture can simplify quality expectations and supply chain transparency for buyers.

Who It's For

This mattress is ideal for parents and caregivers shopping for a replacement or spare mattress for a mini crib, bedside bassinet-style setup, or portable travel crib where standard crib mattresses are too large. Its firm, hypoallergenic core and waterproof cover suit newborns and older infants who need a stable sleeping surface and easy cleanup.

Those who want a plush, pillow-top feel or a mattress sized for standard cribs or pack 'n plays should look elsewhere, since this model is specifically 38L x 24W x 4H and emphasizes firmness and safety over softness or larger dimensions.

Pros & Cons

Pros

• Firm, hypoallergenic fiber core supports infant safety and spinal alignment.
• Waterproof cotton cover simplifies cleaning and protects the mattress interior.
• GREENGUARD Gold certification and compliance testing reduce concerns about chemical emissions.
• Compact dimensions fit most mini and portable cribs without modification.

Cons

• At 4 in thick and firm, it is not designed for parents seeking a softer or more cushioned sleep surface.
• Not suitable for standard cribs or pack 'n plays, so careful measurement is required before purchase.

Specifications

Product name	Simmons Kids SlumberTime Naturally 4-Inch Mini Crib Mattress
Dimensions	38L x 24W x 4H in
Cover	Natural cotton with waterproof backing
Core	Hypoallergenic fiber core made from recycled bottles
Certifications	GREENGUARD Gold; meets flammability, lead, phthalate and CPSIA testing
Made	United States

Our Verdict

The Simmons Kids SlumberTime Naturally 4-Inch Mini Crib Mattress is a practical, safety-focused choice for parents who need a firm, compact mattress for mini or portable cribs. It offers reliable support, a waterproof cotton cover, and strong safety certifications, making it good value for buyers prioritizing infant safety and easy maintenance over plush comfort.

Frequently Asked Questions

Will this fit my mini crib?
Measure your crib interior first; the mattress measures 38L x 24W x 4H and fits most mini and portable cribs but not standard cribs.

Is the cover waterproof?
Yes, it has a naturally blended cotton cover with a waterproof backing to protect the core from spills.

Is it safe for newborns?
Yes, the firm hypoallergenic fiber core and GREENGUARD Gold certification make it appropriate for infant sleep when used with proper bedding and crib safety practices.