Body Swimsuit
For babies under six months, a UPF 50+ rash guard or sun-protective swimsuit isn't a style choice — it's genuinely essential safety gear. Here's why: the American Academy of Pediatrics recommends against applying sunscreen to babies under six months old, except in small amounts on exposed skin when shade truly isn't available. That means UV-protective clothing is your primary — and often your only — recommended line of defense against sun damage for a newborn at the beach or lake.
Look for a suit rated UPF 50+, which blocks at least 98% of UVA and UVB rays. Full-body coverage (long sleeves, leggings) offers the most protection, but even a short-sleeved rashguard is a major upgrade over a standard swimsuit. Pair it with a wide-brimmed hat and seek shade during peak sun hours (10 AM–4 PM) for the best protection overall.
One important note: UV-protective fabric does the one job it's designed for — shielding skin from the sun. It does not make water time safer. A rash guard provides zero protection against drowning risk, so constant, eyes-on, within-arm's-reach supervision near any water remains non-negotiable, regardless of what your baby is wearing.
This is one of those purchases where spending a little more for a well-rated, snug-fitting UPF 50+ suit is genuinely worth it.
Category Primer & Safety Context
Primary Types & Styles
- One-piece rashguard swimsuit (pull-on or snap/zip closure): The dominant infant format. The integrated top-and-bottom design prevents the suit from riding up and exposing the torso — critical for a wriggly newborn who can't pull clothing back down. Snap or zip closures at the bottom exist specifically to enable diaper changes without full removal.
- Two-piece rashguard top + swim bottom set: Popularized by brands like Carter's and SwimZip. More modular and easier to size independently (top and bottom grow at different rates), but creates a midriff gap during movement, reducing full-torso UV coverage.
- Full-coverage sunsuit / "beach romper": Covers from ankles to neck in a single piece. Preferred by dermatologists for maximum UV protection; slightly harder to put on but eliminates virtually all sun-exposed skin below the neck.
- Separate rashguard shirt (no integrated bottom): Designed to layer over a standard swim diaper or trunk. Popular for older infants/toddlers with mix-and-match flexibility, but leaves legs exposed.
Core Function & Lifespan
Provides UPF-rated physical UV barrier over the largest surface area of the body, dramatically reducing the need for chemical or mineral sunscreen on delicate infant skin — particularly important under 6 months of age per AAP guidance.
Lifespan: Typically one swim season per size; most brands size 0–3M through 24M or 3T. A mid-July baby in Maine will likely need 0–3M or 3–6M for late summer, then 6–12M by the following summer.
Key Buying Criteria
- UPF 50+ rating (blocks ≥98% of UVA/UVB rays; UPF 40 is "very good" but 50+ is the gold standard for infants)
- OEKO-TEX Standard 100 or equivalent certification (ensures no harmful dyes or chemicals migrate to sensitive skin)
- Diaper-access design (snaps or full-length zipper at the bottom — non-negotiable for newborns)
Safety Standards & Recalls
- No strict federal safety regulations govern infant swimwear fabric or construction in the United States.
- The CPSC has not issued major category-wide recalls for infant rash guards.
- The AAP recommends UPF 50+ clothing as the primary sun defense for infants under 6 months, with mineral-only (zinc oxide or titanium dioxide, oxybenzone-free) sunscreen as a supplement on exposed areas.
- OEKO-TEX 100 certification is the most meaningful voluntary safety standard to seek.
- Avoid rash guards with loose ties, drawstrings, or decorative hardware near the neck — these are CPSC hazard points for infants.
Top Picks
| Product | Verdict | Price | Key Specs | Pros | Cons | Parent Consensus |
|---|---|---|---|---|---|---|
| Hanna Andersson Baby Rashguard Swimsuit | ⭐ Wirecutter Top Pick; Forbes Best Overall; The Bump Best Overall | ~$48–55 | Recycled fabric; OEKO-TEX; UPF 50+; sizes 0–3M to 3T; back zip + snap crotch | Blocks 97% UV; chlorine- & saltwater-resistant; mock neck; machine washable | Premium price; back zip needs two hands; tops out at 3T | Universally praised on r/BabyBumps and Lucie's List for durability and true-to-size fit |
| SwimZip Baby & Infant UPF 50+ Sunsuit | Forbes "Best for Sun Protection" | ~$35–45 | Nylon/spandex; UPF 50+; full-length front zip; zipper garage; sizes 0–6M+ | Easiest on/off of any option; flat seams; quick-dry; 4.9/5 stars across 3,600+ reviews | Fewer prints; two-piece version leaves midriff gap | Parents of reflux- and eczema-prone babies love the front zip; strong Amazon/direct-site consensus |
| Coolibar UPF 50+ Baby Beach One Piece | BabyGearLab Featured | ~$40–55 | Proprietary SUNTECT® polyester; UPF 50+; ankle-to-neck coverage; front snap + snap crotch; sizes 6M–24M | Maximum skin coverage; lightweight; quick-dry; chlorine-resistant; dermatologist-brand credibility | No newborn size (starts at 6M); runs small; limited styles | Recommended by pediatric dermatologists; praised on r/ScienceBasedParenting for full-body coverage |
| iPlay by Green Sprouts Eco Zip Long-Sleeve Rashguard | Wirecutter "Budget Pick" | ~$15–25 | Recycled fabric; UPF 50+; front zip; OEKO-TEX; sizes 3M–4T | Most affordable UPF 50+ option; eco materials; available at Target & Amazon; starts at 3M | Thinner fabric; modest print selection; less chlorine-durable long-term | Popular "everyday workhorse" on budget parenting forums; valued for fast Prime shipping |
| Patagonia Kids' Capilene® Silkweight Rashguard | REI & Backcountry editorial favorite | ~$45 | 84% recycled polyester/16% spandex; UPF 40+; Fair Trade Certified™; bluesign® approved; starts at 2T | Most sustainable construction; Ironclad Guarantee; raglan sleeves eliminate chafing | Not available in infant sizes (earliest 2T); UPF 40+ falls short of 50+ gold standard | Beloved for toddler+ years on r/Parenting; universally noted as a "grow-into" purchase |
🏆 Category Winners
- Best UV Protection: Hanna Andersson — UPF 50+ with OEKO-TEX certification blocking 97% of UVA/UVB across a full long-sleeve, mock-neck, snap-crotch design with no skin gaps.
- Easiest Diaper Changes (Critical for Newborns): SwimZip — The full-length front zipper with a built-in zipper garage (no metal-on-skin contact) is the fastest, most one-hand-friendly closure system tested — a genuine differentiator when changing a newborn poolside.
- Best Full-Body Sun Coverage: Coolibar — Ankle-to-neck coverage with its proprietary SUNTECT® fabric is the closest thing to "zero exposed skin" in this category, ideal for a pale newborn's first beach visit under Maine's intense summer UV.
- Best Value: iPlay by Green Sprouts — At $15–25 with UPF 50+, OEKO-TEX certification, and availability starting at 3 months, it's the only budget option that doesn't compromise either non-negotiable safety criterion.
⛔ The Dealbreakers
- Patagonia: Does not come in newborn or infant sizes — a hard no for a July baby's first summer.
- Coolibar: No 0–3M or 3–6M sizing; plan to introduce it at the 6-month mark.
- Carter's: Two-piece rashguard sets (~$24) use basic polyester with unverified UPF claims and no OEKO-TEX certification — fine as a backup, but outclassed on safety documentation by every option above.
- Old Navy: UPF ratings are inconsistently labeled across their line and fabric certifications are absent — treat as a fashion item, not a sun-safety item.
- Hanna Andersson back zipper: Secure but requires two hands, which can frustrate diaper changes on a fussy newborn — SwimZip's front zip wins on poolside practicality.
The TL;DR Matchmaker
- Hanna Andersson Baby Rashguard Swimsuit — Best for the parent who wants one premium, do-it-all option with ironclad safety credentials and enough color variety to actually enjoy buying it.
- SwimZip Baby Sunsuit — Best for parents of high-needs or eczema-prone newborns who need the fastest, most one-handed diaper-change experience possible at the pool.
- Coolibar Baby Beach One Piece — Best for parents with a family history of sun sensitivity or those planning a beach-heavy summer starting around 6 months, who want maximum dermatologist-grade coverage.
- iPlay by Green Sprouts Eco Zip Rashguard — Best for the budget-conscious parent who needs a last-minute, Prime-shipped, genuinely safety-certified option without breaking the bank.
- Patagonia Capilene® Silkweight Rashguard — Best for the outdoorsy Maine parent to purchase when the baby turns 2 — a phenomenal long-term investment for hiking, kayaking, and beach days with a toddler, but the wrong tool for a newborn's first summer.