Monofin
Worth a lookShows demand growing +170.8% this quarter, but weak search conversion (1.6%) keeps it on the watch list.
Growth
Incredible+170.8%90-day search growth — must beat 0% to launch
Avg price
Great$54.64avg listing price — sweet spot $15–$100
Competition
Great36%top-5 click share — an open shelf
Review moat
Good1,180.82avg incumbent reviews — the moat a new listing must climb
Quality gap
Okay4.5★avg incumbent rating — lower means beatable quality
Price range
Okay$5.98–$228.28cheapest to priciest tracked listing — scored on the share inside $15–$100
Returns
Okay4.2%return rate — above 5% kills the launch gate
Brand share
Okay87%top-5 brand share — brands hold most of the demand
Market size
Okay$127K$127K/yr · 150K searches
Conversion
Bad1.6%search→purchase rate — share of searches ending in a sale
Is monofin profitable on Amazon?
According to Flapen's Amazon United States niche tracking, monofin is a $127K/yr Amazon United States market (150K searches/yr). The top 5 brands hold 87% of demand. Demand peaks in Jun–Jul–Aug. Verdict: Worth a look — 53/100.
Data updated Jul 26, 2026 · scored weekly · How we score niches
monofin market size & sales
Units sold, revenue, conversion and listing quality across the tracked shelf.- Units sold / yr
- 2K–3K
- avg 0–100/product
- Revenue / yr
- $109K–$137K
- units × avg price
- Conversion rate
- 1.6%
- Avg BSR
- #1,556
- Page quality
- 0%
- Prime
- 75%
- Sponsored
- 78%
- Out of stock
- 2.5%
- Avg brand age
- 49 months
- Avg seller age
- 174 days
Competition: brands, sellers & click share
Clicks spread well past the top 5 (36% combined) — an open shelf where new products get seen.Brands
14 rising
Sellers
21
Top-5 brand share
87%
Top 20: 100%
Top-5 click share
36%
Top 20: 78%
Open market
10%
- Fin Fun30%
- Body Glove23%
- Sun Tails19%
- FINIS7%
- Foyinbet7%
- AIWANK3%
- Open — no brand owns it (8 brands, 10%)
monofin demand & seasonality
Weekly Amazon search volume, last 104 weeks — +170.8% search growth over the last 90 days.Peak months: Jun, Jul, Aug · busiest ÷ quietest = 6.1×
Top monofin search terms shoppers use
The exact queries shoppers type, with yearly volume, growth and conversion.- monofin50K/yr
- monofin adult18K/yr
- mermaid fin17K/yr
- mermaid fins for girls11K/yr
- mono fin6K/yr
- adult monofin5K/yr
- monofin for kids6K/yr
- mermaid monofin6K/yr
- mermaid fins7K/yr
- mermaid fin for swimming7K/yr
Top monofin products & what they sell for
Every tracked product — its share of the shelf, its review moat, and what it sells for.Each bubble is one product — market share against review moat; bubble size tracks estimated sales, color grades how beatable the incumbent looks.
All 24 tracked products in this niche — three views at once, no toggling.
Top sellers
by 90-day click share
Mermaid Linden Kids Monofin - Pink
Body Glove$42.594.6★2,608 rev
Fin Fun Mermaid Monofin Swim Fin for Kids and Adults (Blue Trim Black Junior - Ages 6-11)
Fin Fun$33.334.6★3,347 rev
Mermaid Linden Kids Monofin-Blue
Body Glove$38.864.6★2,608 rev
Fin Fun Mermaid Monofin - Swim Fin for Kids & Adults Ages 12 and Up - Swimming Flipper with Comfortable Foot Pockets - Snorkel & Water Accessory Made w/ Dive-Grade Neoprene - (Blue Trim Black Pro)
Fin Fun$38.674.6★3,347 rev
Sun Tails Mermaid Monofin (Turquoise Nunui - Teen/Adult Size)
Sun Tails$49.024.4★381 rev
Newest
by launch date
Fin Fun Mermaid Monofin - Swim Fin for Kids Ages 6-11 - Swimming Flipper with Comfortable Foot Pockets - Snorkel & Water Accessory Made w/ Dive-Grade Neoprene - JR Small
Fin Fun$34.043,347 rev
Fin Fun Mermaid Monofin - Swim Fin for Kids & Adults Ages 12 and Up - Swimming Flipper with Comfortable Foot Pockets - Snorkel & Water Accessory Made w/ Dive-Grade Neoprene - Pro Small
Fin Fun$39.083,347 rev
Fin Fun Asian Magenta Mermaid Tail with Monofin Women & Teens XS
Fin Fun$73.1419 rev
Mermaid Linden Adult Monofin - BLK/SIL
Body Glove$69.4724 rev
Mermaid Linden Adult Monofin - Ultramarine Purple
Body Glove$69.5014 rev
Trending
90-day click momentumFin Fun Mermaid Monofin - Swim Fin for Kids Ages 6-11 - Swimming Flipper with Comfortable Foot Pockets - Snorkel & Water Accessory Made w/ Dive-Grade Neoprene - JR Small
Fin Fun$34.044.6★
Fin Fun Mermaid Monofin - Swim Fin for Kids & Adults Ages 12 and Up - Swimming Flipper with Comfortable Foot Pockets - Snorkel & Water Accessory Made w/ Dive-Grade Neoprene - Pro Small
Fin Fun$39.084.6★
Mermaid Tail and Monofin for Swimming with MER-Shield Tip Protection Adult Sizes (Bali Blush - Purple Monofin Adult L (JL 12-16))
Sun Tails$79.914.5★
Foyinbet Kids Swim Fins Short Kids Fins Youth Swimming Flippers for Lap Swimming Training for Children Girls Boys Beginners 2XS
Foyinbet$27.734.6★
Sun Tails Mermaid Monofin (Green Keiki - Child Size)
Sun Tails$44.334.4★
What reviews say buyers love and hate about monofin
What buyers praise and complain about, mined from review topics.What buyers love
“Fits PERFECTLY”
“Great build quality”
“Definitely worth the cost”
“It is comfortable”
“Exactly as described”
“My child was heartbroken because it is such a fun monofin”
“It is very durable”
“has great propulsion in the water”
“can easily use these”
“lightweight blanket”
What buyers complain about
“Tight”
“The 1st one the snaps and straps broke”
“Broke after a few uses”
“Lowkey dangerous & also uncomfortable hehe”
“Too heavy”
“its hard to get on quickly”
“hurts to put on”
“Does not work”
“I do not see how that can be accurate”
“Maybe this should not be advertised for small children”
Top return reasons
Common monofin questions
- Is monofin profitable to sell on Amazon United States?
- The niche generates $127K/yr across 51 tracked products. 8 of 10 products launched in the last 360 days are still selling. 90-day search growth is +170.8%. Flapen's verdict: Worth a look (53/100).
- How competitive is the monofin niche?
- 14 brands and 21 sellers compete. The top 5 products take 36% of clicks and top 5 brands hold 87% of demand.
- What do buyers complain about in monofin?
- Top complaints mined from reviews: Size-Overall, Strap/String Quality, Durability. The return rate is 4.2%.
- When does demand for monofin peak?
- Demand peaks in Jun–Jul–Aug; the busiest month runs 6.1× the quietest.
- What does it cost to enter the monofin niche?
- Listings span $5.98–$228.28; the average listing price is $54.64 (sweet spot $15–$100). The average incumbent carries 1,181 reviews — the moat a new listing must climb.