---
title: "Boys Long Underwear Size 10-12 — $47K/yr Amazon US Niche (2026) - Flapen"
canonical_url: "https://flapen.com/research/us/clothing-shoes-jewelry/boys-long-underwear-size-10-12"
last_updated: "2026-08-10T19:51:41.946Z"
locale: en
meta:
description: "Niche score 40/100 · $47K/yr market · 51K searches/yr · $20.78 avg price. Doesn't clear our bar today. Data updated Jul 2026."
"og:description": "Niche score 40/100 · $47K/yr market · 51K searches/yr · $20.78 avg price. Doesn't clear our bar today. Data updated Jul 2026."
"og:title": "Boys Long Underwear Size 10-12 — $47K/yr Amazon US Niche (2026) - Flapen"
---
# **boys long underwear size 10-12**
**Skip it**
Soft demand (-76.6% this quarter) — this niche doesn't clear our bar today.
Market size 12Growth 0Conversion 54Competition 70Returns 18Price range 84Avg price 89Brand share 70Review moat 60Quality gap 18
**Avg price**
**Great****$20.78**
avg listing price — sweet spot $15–$100
**Price range**
**Great****$12.12–$32.24**
cheapest to priciest tracked listing — scored on the share inside $15–$100
**Competition**
**Good****43%**
top-5 click share — leaders hold, buyers still browse
**Brand share**
**Good****63%**
top-5 brand share — brands hold most of the demand
**Review moat**
**Good****1,113.89**
avg incumbent reviews — the moat a new listing must climb
**Conversion**
**Good****4.5%**
search→purchase rate — share of searches ending in a sale
**Quality gap**
**Bad****4.7★**
avg incumbent rating — lower means beatable quality
**Returns**
**Bad****6.9%**
return rate — above 5% kills the launch gate
**Market size**
**Bad****$47K**
$47K/yr · 51K searches
**Growth**
**Bad****-76.6%**
90-day search growth — must beat 0% to launch
**Signals**[** High Returns**](https://flapen.com/research/niches?market=us&signal=high_returns "Return rate > 5%")
According to Flapen's Amazon United States niche tracking, boys long underwear size 10-12 is a $47K/yr Amazon United States market (51K searches/yr). The top 5 brands hold 63% of demand. Demand peaks in Jan–Feb–Oct–Nov–Dec. Verdict: Skip it — 40/100.
Data updated Jul 8, 2026 · scored weekly · [~~How we score niches ~~](https://flapen.com/research/methodology)
## **boys long underwear size 10-12 market data**
- **Units sold / yr**
- **2K–2K**
- avg 0–100/product
- **Revenue / yr**
- **$31K–$42K**
- units × avg price
- **Conversion rate**
- **4.5%**
- **Avg BSR**
- **#13**
- **Page quality**
- **0%**
- **Prime**
- **100%**
- **Sponsored**
- **89%**
- **Out of stock**
- **6.3%**
- **Avg brand age**
- **44 months**
- **Avg seller age**
- **136 days**
## **Competition & brand share**
The top 5 products take 43% of clicks — established leaders, but buyers still shop beyond them.
**Brands**
**20 **▼falling
**Sellers**
**24**
**Top-5 brand share**
**63%**
Top 20: 100%
**Top-5 click share**
**43%**
Top 20: 80%
**Open market**
**31%**
- Spyder30% - TELALEO10% - Runhit8% - Rolimaka8% - Ewedoos7% - Cuddl Duds6%
## **Demand & seasonality**
Weekly Amazon search volume, last 104 weeks — -76.6% search growth over the last 90 days.
4K3KPrime Day '24Spike '24Holiday '24Spike '25Prime Day '25Black Friday '25Holiday '25Spike '26 seasonSepDecMarJunAugNovMarMay
Peak months: Jan, Feb, Oct, Nov, Dec · busiest ÷ quietest = 14.7×
[**Open Trend **](https://flapen.com/research/us/clothing-shoes-jewelry/boys-long-underwear-size-10-12/trend)
## **Top boys long underwear size 10-12 search terms**
- **youth thermal base layer**12K/yr-78.6%1.4% conv. - **boys long underwear size 10-12**7K/yr-67.8%3.4% conv. - **boys long underwear size 14-16**5K/yr-62.4%2.9% conv. - **kids long underwear boys**3K/yr-45.1%2.5% conv. - **base layer boys**4K/yr-68.8%0.9% conv. - **4t thermals for boys**7K/yr-87.8%2.7% conv. - **5t thermals for boys**6K/yr-90.5%2.3% conv. - **boys long johns size 10-12**3K/yr-76.1%3.0% conv. - **boys long johns size 14-16**3K/yr-85.5%0.0% conv. [**All search terms **](https://flapen.com/research/us/clothing-shoes-jewelry/boys-long-underwear-size-10-12/search-terms)
## **Top boys long underwear size 10-12 products on Amazon**
Each bubble is one product — market share against review moat; bubble size tracks estimated sales, color grades how beatable the incumbent looks.
0%5%$2K10%$5K15%$7K20%$9K101001K10K Reviews — right = deep review moatMarket share (90d) ≈ est. sales
Beatable (≤4.3★) Contested Strong incumbent (>4.7★)
All 24 tracked products in this niche — three views at once, no toggling.
### **Top sellers**
by 90-day click share
[1**Spyder Kids Thermal Underwear Set - 2 Piece Soft Stretch Moisture Wicking Girls Boys Thermal Set Long Johns for Kids Size 16-18 Black**Spyder**$20.91**4.7★208 rev](https://www.amazon.com/dp/B0DJRRFKVB) [2**Runhit Thermal Underwear for Kids Long Johns Ultra Soft Long Sleeve Shirts Sets Skiing Base Layer Fleece Lined Pants Suit Black M**Runhit**$12.86**4.7★632 rev](https://www.amazon.com/dp/B0CCR8TQTP) [3**Spyder Kids Thermal Underwear Set - 2 Piece Soft Stretch Moisture Wicking Girls Boys Thermal Set Long Johns for Kids Size 16-18 Heather Grey**Spyder**$20.49**4.7★208 rev](https://www.amazon.com/dp/B0DJRRCMKD) [4**TELALEO Boys Girls Thermal Set Fleece Lined Underwear Set Kids Compression Shirts Athletic Sports Tops Leggings Baselayer Shirts/Pants Set M**TELALEO**$18.55**4.8★2,926 rev](https://www.amazon.com/dp/B0841X35YN) [5**Ewedoos Thermal Underwear Set for Kids Thermals Top and Bottom Set Boys Long Johns Base Layer Thermal Set Black**Ewedoos**$15.91**4.8★517 rev](https://www.amazon.com/dp/B0CBKND1FK)
**~~View all top sellers →~~**
### **Newest**
by launch date
[**HXP Boys Compression Thermal Base Layer Set Athletic Youth Fleece Lined Long Sleeve Sports Tops Leggings for Kids Black M**HXP**$12.12**85 rev6mo ago](https://www.amazon.com/dp/B0G29ZW8F9) [**Zando Boys Thermal Underwear Set - Kids Thermals Top and Bottom Winter Warm Kids Long Johns 4T Fleece Lined Compression Shirt Leggings Thermal Base Layer for Boys Girls Cold Weather 2 Set Black 5T**Zando**$22.88**85 rev10mo ago](https://www.amazon.com/dp/B0FN86B8NW) [**Spyder Kids Thermal Underwear Set - 2 Piece Soft Stretch Moisture Wicking Girls Boys Thermal Set Long Johns for Kids Size 16-18 Black**Spyder**$20.91**208 rev1y ago](https://www.amazon.com/dp/B0DJRRFKVB) [**Spyder Kids Thermal Underwear Set - 2 Piece Soft Stretch Moisture Wicking Girls Boys Thermal Set Long Johns for Kids Size 16-18 Heather Grey**Spyder**$20.49**208 rev1y ago](https://www.amazon.com/dp/B0DJRRCMKD) [**Spyder Kids Thermal Underwear Set - 2 Piece Soft Stretch Moisture Wicking Girls Boys Thermal Set Long Johns for Kids Size 8-10 Black**Spyder**$23.03**208 rev1y ago](https://www.amazon.com/dp/B0DJRQKW5M)
**~~View all new products →~~**
### **Trending**
90-day click momentum
[**BAMBOO COOL Boys Underwear Moisture-Wicking Brethable Boxer Briefs Soft Lightweight Tag-Free with Fly Pouch 6-Pack**BAMBOO COOL**$32.24**4.8★**▲ 352%**](https://www.amazon.com/dp/B0D2L42K5X) [**Runhit Thermal Underwear for Kids Long Johns Ultra Soft Long Sleeve Shirts Sets Skiing Base Layer Fleece Lined Pants Suit Black M**Runhit**$12.86**4.7★**▲ 348%**](https://www.amazon.com/dp/B0CCR8TQTP) [**HXP Boys Compression Thermal Base Layer Set Athletic Youth Fleece Lined Long Sleeve Sports Tops Leggings for Kids Black M**HXP**$12.12**4.7★**▲ 309%**](https://www.amazon.com/dp/B0G29ZW8F9) [**Spyder Kids Thermal Underwear Set - 2 Piece Soft Stretch Moisture Wicking Girls Boys Thermal Set Long Johns for Kids Size 16-18 Black**Spyder**$20.91**4.7★**▲ 196%**](https://www.amazon.com/dp/B0DJRRFKVB) [**G Gradual Youth Boys Compression Thermal Shirt Long Sleeve Fleece Undershirt for Boy Football Baseball Soccer Base Layer(Black XS)**G Gradual**$16.20**4.8★**▲ 172%**](https://www.amazon.com/dp/B0CJ85B5PN)
**~~View all trending →~~**
## **What buyers say about boys long underwear size 10-12**
What buyers praise and complain about, mined from review topics.
### **What buyers love **
**Size-Overall**23%
*“Fit great”*
**Warmth**19%
*“Keep warm”*
**Comfort-Overall**13%
*“Very comfortable”*
**Quality-Overall**11%
*“Excellent quality, perfect fit, delivered just in time”*
**Soft Feel**5%
*“Soft and comfortable”*
**Value For Money**3%
*“Affordable long underwear for kids”*
**Durability**2%
*“Durable, good quality”*
**Material Quality**2%
*“The material was comfortable”*
**Stretchability/Expandability/Elasticity**2%
*“Nice stretch too”*
**Moist/Dry**1%
*“The moisture-wicking feature works great for an active boy”*
### **What buyers complain about **
**Size-Overall**23%
*“Size is 2 sizes tighter than it shouldve been”*
**Quality-Overall**13%
*“Disappointing Quality for Kids' Thermal Set”*
**Material Quality**11%
*“Cheap material”*
**Thickness**4%
*“The material isnt too thick”*
**Waist Fit**4%
*“And while the waist fits the length is way too short”*
**Length**4%
*“Very long”*
**Sleeve Fit**2%
*“it was sorta long on the sleeves I had to fold them”*
**Smell**2%
*“smells chemically out of package”*
**Stretchability/Expandability/Elasticity**2%
*“the set hasnt stretched out”*
**Thin**1%
*“Just a little thin”*
### **Top return reasons **
**Size-Overall**62%
**Length**7%
**Waist Fit**7%
**Material Quality**3%
**Sleeve Fit**2%
**Thigh Fit**2%
**Advertised Vs Actual Product**2%
**Thin**1%
**Value For Money**1%
**Compression**1%
## **Common questions**
- **Is boys long underwear size 10-12 profitable to sell on Amazon United States?**
- The niche generates $47K/yr across 38 tracked products. 0 of 6 products launched in the last 360 days are still selling. 90-day search growth is -76.6%. Flapen's verdict: Skip it (40/100).
- **How competitive is the boys long underwear size 10-12 niche?**
- 20 brands and 24 sellers compete. The top 5 products take 43% of clicks and top 5 brands hold 63% of demand.
- **What do buyers complain about in boys long underwear size 10-12?**
- Top complaints mined from reviews: Size-Overall, Quality-Overall, Material Quality. The return rate is 6.9% — above our launch gate.
- **When does demand for boys long underwear size 10-12 peak?**
- Demand peaks in Jan–Feb–Oct–Nov–Dec; the busiest month runs 14.7× the quietest.
- **What does it cost to enter the boys long underwear size 10-12 niche?**
- Listings span $12.12–$32.24; the average listing price is $20.78 (sweet spot $15–$100). The average incumbent carries 1,114 reviews — the moat a new listing must climb.
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