swim diapers size 4
Launch itA $1.5M/yr market growing +170.0% this quarter with returns at 2.4% — clears our launch bar.
Conversion
Incredible26.8%search→purchase rate — share of searches ending in a sale
Growth
Incredible+170.0%90-day search growth — must beat 0% to launch
Market size
Great$1.5M$1.5M/yr · 355K searches
Avg price
Great$16.17avg listing price — sweet spot $15–$100
Returns
Good2.4%return rate — above 6% kills the launch gate
Competition
Good54%top-5 click share — leaders hold, buyers still browse
Review moat
Okay2,645.7avg incumbent reviews — the moat a new listing must climb
Price range
Okay$6.40–$20.40cheapest to priciest tracked listing — scored on the share inside $15–$100
Quality gap
Okay4.6★avg incumbent rating — lower means beatable quality
Brand share
Bad91%top-5 brand share — brand-locked demand
According to Flapen's Amazon United States niche tracking, swim diapers size 4 is a $1.5M/yr Amazon United States market (355K searches/yr). The top 5 brands hold 91% of demand. Demand peaks in May–Jun–Jul. Verdict: Launch it — 64/100.
Data updated Jul 8, 2026 · scored weekly · How we score niches
Market data
- Units sold / yr
- 80K–100K
- avg 4,000–5,000/product
- Revenue / yr
- $1.3M–$1.6M
- units × avg price
- Launch success
- —
- 1 of 3 new (360d)
- Conversion rate
- 26.8%
- Avg BSR
- #16
- Page quality
- 0%
- Prime
- 100%
- Sponsored
- 100%
- Out of stock
- 12.3%
- Avg brand age
- 50 months
- Avg seller age
- 154 days
Competition
The top 5 products take 54% of clicks — established leaders, but buyers still shop beyond them.Brands
9 rising
Sellers
11
Top-5 brand share
91%
Top 20: 100%
Top-5 click share
54%
Top 20: 96%
Open market
6%
- MooMoo Baby50%
- Hello Bello19%
- EZ Moms8%
- MomEasier7%
- ALVA7%
- babygoal3%
- Open — no brand owns it (3 brands, 6%)
Demand & seasonality
Weekly Amazon search volume, last 104 weeks — +170.0% search growth over the last 90 days.Peak months: May, Jun, Jul · busiest ÷ quietest = 8.6×
Product shelf
Each bubble is one product — market share against review moat; bubble size tracks estimated sales, color grades how beatable the incumbent looks.
All 23 tracked products in this niche — three views at once, no toggling.
Top sellers
by 90-day click share
Hello Bello Premium Swim Diapers I Affordable and Eco-Friendly Disposable Swim Dipes for Babies and Kids I Size Medium
Hello Bello$13.414.6★1,260 rev
MooMoo Baby Swim Diapers 3 Pcs Waterproof Reusable Swim Diapers for Baby Swim Lesson 4T
MooMoo Baby$18.944.7★483 rev
MooMoo Baby Reusable Swim Diapers 3 Pcs Waterproof Swimming Diapers for Baby Swim Lesson
MooMoo Baby$19.044.7★483 rev
MooMoo Baby Reusable Swim Diapers 3 Pcs Waterproof Swimming Diapers for Baby Swim Lesson
MooMoo Baby$19.144.7★483 rev
MomEasier Swim Diapers 3 Pcs Reusable Swimming Diaper for Baby Boys and Girls 2-5T Green
MomEasier$20.404.6★26 rev
Newest
by launch dateMomEasier Swim Diapers 3 Pcs Reusable Swimming Diaper for Baby Boys and Girls 2-5T Green
MomEasier$20.4026 rev
MomEasier Swim Diapers 3 Pcs Reusable Swimming Diaper for Baby Boys and Girls 2-5T Green
MomEasier$20.2826 rev
Nuby Swim Pants for Toddlers - 5 Pack - Toddler Swim Diapers with Stretchy Waistline Tear-Away Sides Water-Resistant Outer Layer & Leak-Preventing Cuffs - Size Medium (20-31 lbs)
Nuby$6.4046 rev
BIG ELEPHANT Baby Swim Diapers 3-Pack Reusable Waterproof Swim Pants for Boys and Girls Soft Breathable Swimwear for Pool
BIG ELEPHANT$16.5254 rev
MooMoo Baby Reusable Swim Diapers 3 Pcs Waterproof Swimming Diapers for Baby Swim Lesson 4T
MooMoo Baby$18.60483 rev
Trending
90-day click momentumMomEasier Swim Diapers 3 Pcs Reusable Swimming Diaper for Baby Boys and Girls 2-5T Green
MomEasier$20.284.6★
MomEasier Swim Diapers 3 Pcs Reusable Swimming Diaper for Baby Boys and Girls 2-5T Green
MomEasier$20.404.6★
MooMoo Baby Reusable Swim Diapers 3 Pcs Waterproof Swimming Diapers for Baby Swim Lesson
MooMoo Baby$19.054.7★
MooMoo Baby Reusable Swim Diapers 3 Pcs Waterproof Swimming Diapers for Baby Swim Lesson
MooMoo Baby$19.144.7★
BIG ELEPHANT Baby Swim Diapers 3-Pack Reusable Waterproof Swim Pants for Boys and Girls Soft Breathable Swimwear for Pool
BIG ELEPHANT$16.524.4★
Reviews
What buyers praise and complain about, mined from review topics.What buyers love
“Fit well”
“Good quality”
“stretchy”
“they're soft and water resistant”
“They are super comfortable”
“They're adjustable and cute colors”
“Easy to use”
“They are super soft”
“The design is super cute”
“These are a good value”
What buyers complain about
“fits awkwardly”
“Does not absorb water well - diaper always appears to look loaded down My daughter is a 4T in clothing”
“Just a little complex to put on”
“my son broke-out with a rash from wearing this swim diaper”
“These do NOT work at all”
“The buttons press on the hips a little”
“The price is higher per diaper”
“The material is thick”
“a bit tight at the seams”
“they are not adjustable”
Top return reasons
Common questions
- Is swim diapers size 4 profitable to sell on Amazon United States?
- The niche generates $1.5M/yr across 23 tracked products. 1 of 3 products launched in the last 360 days are still selling. 90-day search growth is +170.0%. Flapen's verdict: Launch it (64/100).
- How competitive is the swim diapers size 4 niche?
- 9 brands and 11 sellers compete. The top 5 products take 54% of clicks and top 5 brands hold 91% of demand.
- What do buyers complain about in swim diapers size 4?
- Top complaints mined from reviews: Size-Overall, Water Resistance, Ease Of Use. The return rate is 2.4%.
- When does demand for swim diapers size 4 peak?
- Demand peaks in May–Jun–Jul; the busiest month runs 8.6× the quietest.
- What does it cost to enter the swim diapers size 4 niche?
- Listings span $6.40–$20.40; the average listing price is $16.17 (sweet spot $15–$100). The average incumbent carries 2,646 reviews — the moat a new listing must climb.
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