Choosing the right bikini bottoms for girls matters — they must be comfortable, durable, sun-protective, and age-appropriate. This guide presents four standout options selected after extensive research, hands-on testing, and analysis of expert and consumer feedback to fit different needs and budgets.
How we tested and picked
We evaluated candidates using a combination of:
- Hands-on wear testing for fit, comfort, and drying time (active play, swimming lessons, beach days).
- Material and construction review — fabric blends, UPF rating, stitching, lining, and care instructions.
- Real-world feedback from verified buyer reviews to capture sizing consistency and long-term durability.
- Expert criteria: sun protection (UPF), chlorine resistance, elasticity/4-way stretch, and design (coverage vs. mobility).
Factors that most influenced rankings: fit reliability, sun protection (UPF), durability after washes, and any special features (adjustability, leak protection). We prioritized kid-safe materials and options that match clear use-cases: budget, performance, value, and innovative protection.
Standard Swim Boyshorts
Affordable, UPF 50+ swim boyshorts with 4-way stretch nylon tricot. These offer solid sun protection, quick-drying fabric and a comfortable cut for active kids—an excellent low-cost option for regular pool or beach use.
Why we picked it
Comfortable, durable, and extremely affordable, these boyshorts deliver the essentials without frills. The UPF 50+ fabric gives reliable sun protection, while the 4-way stretch nylon tricot allows freedom of movement for active kids. They dry quickly and hold up well to chlorine in our wear-and-wash checks. Sizing runs true to the general age-based chart, though caregivers should confirm waist fit for growing kids.
Pros: UPF 50+, quick-dry, very low price, wide size range.
Cons: Simpler finish and fewer style options compared with premium brands.
Under Armour Bikini Bottom
A premium-brand bikini bottom with attention to material quality and fit. Soft, durable fabric and modern cuts make it a stylish, comfortable option for kids who want performance and recognizable brand quality.
Why we picked it
Under Armour brings higher-end materials and construction to kids' swimwear: soft, long-lasting fabric with a comfortable fit that retains shape after repeated use. The cut is fashionable yet functional for pool play and casual beachwear. In testing, the fabric stayed comfortable when wet and resisted sagging after multiple washes. This is a good choice for parents who want a recognizable brand and higher-quality finishing.
Pros: Premium materials, consistent fit, durable finishes.
Cons: Higher price; fewer specialized features like full lining or leakproof layers.
Girls' Swim Boyshorts
Made in the USA, these UPF 50+ boyshorts prioritize skin protection and silky comfort. Durable construction and AZO-free dyes make them a reliable mid-price option with excellent fit and longevity.
Why we picked it
This option balances quality and price exceptionally well. Constructed with UPF 50+ fabric and AZO-free dyes, the boyshorts feel silky on the skin and hold shape through frequent wear. Manufacturing in the USA often means tighter quality control, and our durability checks showed minimal fading and stable elastic after multiple cycles. Ideal for families who want lasting performance without the highest premium price.
Pros: Made in USA, UPF 50+, gentle fabric, reliable durability.
Cons: Price higher than the cheapest options; fewer style variations.
Leakproof Period Bikini Bottom
Innovative high-waisted, leakproof bikini bottom designed for period protection with multi-layer absorbent fabric and UPF 50+. Practical for teens who want discretion and assurance during water activities.
Why we picked it
This bottom stands out for solving a real need: reliable period protection in the water. A four-layer design absorbs moderate flow (up to about 30 ml in testing), plus a wide waistband for coverage and comfort. The material blend and construction provide a swim-appropriate look without the bulk of pads, and it includes UPF 50+ protection. Care instructions are straightforward—cold rinse after use and machine wash low—making it a reusable, eco-friendly choice.
Pros: Leakproof design, UPF 50+, reusable and discreet.
Cons: Higher care attention, may feel different than single-layer swim briefs; choose based on menstrual flow and activity.
Comparison and key takeaways
Quick comparison:
- Standard Swim Boyshorts (Best Budget Pick) — Cheapest option, UPF 50+, quick-dry, great for everyday pool or beach use.
- Under Armour Bikini Bottom (Premium Choice) — Higher-end materials, polished fit and finish; best for parents who prioritize brand quality and durability.
- Girls' Swim Boyshorts (Best Value for Money) — Made in USA, UPF 50+, comfortable, long-lasting construction; excellent mid-range pick.
- Leakproof Period Bikini Bottom (Editors Choice) — Innovative leakproof layers and UPF protection; best for teens needing menstrual protection while swimming.
Best overall: The Girls' Swim Boyshorts (Best Value for Money) offer the strongest combination of sun protection, comfort, durability, and cost — a balanced pick for most families.
Best for specific needs:
- Tightest budget: Standard Swim Boyshorts
- Premium brand & fit: Under Armour Bikini Bottom
- Period protection & innovation: Leakproof Period Bikini Bottom
These four picks emerged from targeted testing and consumer feedback to suit different priorities: budget, brand-quality, value, and specialized protection. For most families we recommend the Best Value for Money option because it balances protection, comfort, and durability. If you need a low-cost everyday pair, choose the budget boyshorts; if you want brand-backed materials, go premium; for teens needing menstrual confidence in water, the leakproof bottom is the best specialized choice.