Is pool liner 21 ft round above ground profitable to sell on Amazon United States?

The niche generates $125K/yr across 30 tracked products. 2 of 4 products launched in the last 360 days are still selling. 90-day search growth is +90.8%. Flapen's verdict: Worth a look (53/100).

How competitive is the pool liner 21 ft round above ground niche?

8 brands and 21 sellers compete. The top 5 products take 49% of clicks and top 5 brands hold 98% of demand.

What do buyers complain about in pool liner 21 ft round above ground?

Top complaints mined from reviews: Assembly/Installation, Stitch/Finish/Polish, Size-Overall. The return rate is 1.1%.

What does it cost to enter the pool liner 21 ft round above ground niche?

Listings span $48.38–$393.61; the average listing price is $256.20 (sweet spot $15–$100). The average incumbent carries 469 reviews — the moat a new listing must climb.

pool liner 21 ft round above ground

Worth a look

Shows low returns (1.1%), but brand-locked demand (top 5 brands take 98% of clicks) keeps it on the watch list.

Returns

Great1.1%

return rate — above 5% kills the launch gate

Growth

Great+90.8%

90-day search growth — must beat 0% to launch

Review moat

Great468.77

avg incumbent reviews — the moat a new listing must climb

Quality gap

Good4.3★

avg incumbent rating — lower means beatable quality

Competition

Good49%

top-5 click share — leaders hold, buyers still browse

Avg price

Okay$256.20

avg listing price — sweet spot $15–$100

Conversion

Okay2.9%

search→purchase rate — share of searches ending in a sale

Market size

Okay$125K

$125K/yr · 17K searches

Price range

Bad$48.38–$393.61

cheapest to priciest tracked listing — scored on the share inside $15–$100

Brand share

Bad98%

top-5 brand share — brand-locked demand

Signals High Price

According to Flapen's Amazon United States niche tracking, pool liner 21 ft round above ground is a $125K/yr Amazon United States market (17K searches/yr). The top 5 brands hold 98% of demand. Verdict: Worth a look — 53/100.

Data updated Jul 24, 2026 · scored weekly · How we score niches

pool liner 21 ft round above ground market data

Units sold / yr: 100–250; avg 0–100/product
Revenue / yr: $26K–$64K; units × avg price
Conversion rate: 2.9%
Avg BSR: #89
Page quality: 0%
Prime: 27%
Sponsored: 93%
Out of stock: 8.1%
Avg brand age: 36 months
Avg seller age: 197 days

Competition & brand share

The top 5 products take 49% of clicks — established leaders, but buyers still shop beyond them.

Brands

8 falling

Sellers

Top-5 brand share

98%

Top 20: 100%

Top-5 click share

49%

Top 20: 90%

Open market

Smartline44%
Swimline25%
Blue Wave21%
VEVOR7%
Shop Square1%
TIXANF1%
Open — no brand owns it (2 brands, 1%)

Demand

Weekly Amazon search volume, last 8 weeks — +90.8% search growth over the last 90 days.

Open Trend

Top pool liner 21 ft round above ground search terms

21 round pool liner5K/yr +128.0%1.4% conv.
21 ft round pool liner4K/yr +102.7%1.7% conv.
21 foot pool liner3K/yr +141.5%1.6% conv.
pool liner 21 ft round above ground4K/yr +24.2%1.9% conv.

All search terms

Top pool liner 21 ft round above ground 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.

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

Swimline 21 Foot Round Durable 20 Gauge Vinyl Wall Overlap Pool Cover Liner for 48 and 52 Inch Above Ground Swimming Pools Blue

Swimline$201.434.4★972 rev

Blue Wave Emerald Coast 21 ft Round Pool Liner for Above Ground Pools

Blue Wave$266.664.0★99 rev

Smartline$308.364.5★777 rev

Blue Wave Evening Bay 21-ft Round Overlap Pool Liner for Above-Ground Steel Wall Pools Weather-Resistant Standard-Gauge Vinyl with Welded Seams for 48/54-In Depth Walls - Dark Blue

Blue Wave$302.154.0★194 rev

Swimline LI214820 21 Foot Solid Blue Round Above Ground Swimming Pool Overlap Liner 20 Gauge Vinyl Liner for 48 to 52 Foot Pool Walls

Swimline$167.354.3★1,069 rev

Newest

by launch date

Smartline$262.66256 rev

5mo ago

Smartline$349.45120 rev

9mo ago

Smartline$219.98435 rev

9mo ago

Swimline Unibead Pool Liner for Above Ground Pools StoneHarbor 21 (Round) 52 Inch Wall 25 Gauge

Swimline$369.6528 rev

1y ago

Swimline Overlap Pool Liner for Above Ground Pools Bedrock 21 (Round) 48/52 Inch Wall 25 Gauge

Swimline$298.7544 rev

1y ago

What buyers say about pool liner 21 ft round above ground

What buyers praise and complain about, mined from review topics.

What buyers love

Size-Overall15%

“Fit well”

Assembly/Installation14%

“Easy to install”

Quality-Overall12%

“Good quality”

Material Quality11%

“The material feels durable and does a great job of protecting the liner from rocks, roots, or uneven ground”

Thickness9%

“Its better than the grass being thick all around it”

Weight Heavy9%

“It very heavy duty weighted almost as much as new liner”

Design-Overall3%

“Its beautiful and very classy”

Strength3%

“Its sturdy and great quality”

Ease Of Use2%

“It was easy to lay out”

Drop/Impact Protection2%

“Great protection for your pool”

What buyers complain about

Assembly/Installation23%

“Wish I had seen the issue before installing”

Stitch/Finish/Polish18%

“The seams didnt match up so the liner has creases”

Size-Overall14%

“it barely fits”

Durability9%

“Have only had it for a week, very disappointed”

Thickness5%

“Was thicker than the old one”

Design-Overall5%

“HOWEVER the Universal Bead is a tough design”

Material Quality5%

“Could be a little stronger material”

Plant Growth5%

“Weeds grow through it be weary of purchasing this”

Top return reasons

Size-Overall53%

Advertised Vs Actual Product7%

Thin6%

Stitch/Finish/Polish5%

Quality-Overall4%

Thickness3%

Material Quality3%

Shape/Style3%

Assembly/Installation2%

Maintenance And Repair2%

Common questions

Is pool liner 21 ft round above ground profitable to sell on Amazon United States?: The niche generates $125K/yr across 30 tracked products. 2 of 4 products launched in the last 360 days are still selling. 90-day search growth is +90.8%. Flapen's verdict: Worth a look (53/100).
How competitive is the pool liner 21 ft round above ground niche?: 8 brands and 21 sellers compete. The top 5 products take 49% of clicks and top 5 brands hold 98% of demand.
What do buyers complain about in pool liner 21 ft round above ground?: Top complaints mined from reviews: Assembly/Installation, Stitch/Finish/Polish, Size-Overall. The return rate is 1.1%.
What does it cost to enter the pool liner 21 ft round above ground niche?: Listings span $48.38–$393.61; the average listing price is $256.20 (sweet spot $15–$100). The average incumbent carries 469 reviews — the moat a new listing must climb.