“I love this thing... it's the Dyson of pool vacs. So much fine dirt is trapped in the filters... I know I'm swimming in a clean pool with clean water.”Kevin E.Verified buyer
Dolphin Sigma Certified Open Box
Our Most High-Tech Robot Yet.
Three Commercial Motors · Quad Brushes · Gyroscopic Navigation
$2299
$2999
3 Year Warranty
30 Day Trial
Certified Open Box
Open Box Dolphin Sigma Robotic Pool Cleaner
$2999 $2299 SALE Save $700
Save hundreds on a Certified Open Box Dolphin Sigma robotic pool cleaner. With gyroscope, NanoFilters, and 3 year warranty, try for 30 days.
- Certified Open Box Dolphin Pool Cleaner
- Includes all parts and accessories
- Fully tested and inspected with Maytronics testing software
- Full 3 Year Warranty + 30 Day Trial
Add Accessories
$149
$145
$99
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Free 1-3 Day FedEx Shipping
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3 Year Warranty Included
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30 Day Trial & No Restocking Fees
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Price Match Guarantee
SAVE BIG ON CERTIFIED OPEN BOX
What is Certified Open Box?
It's a way to enjoy top-quality Dolphin robotic pool cleaners at a fraction of the original cost. Each item has been carefully inspected and tested to ensure it meets the highest standards, offering you the same performance and reliability as a new Dolphin Sigma. Certified Open Box items are fully functional, in like-new condition, and come with full warranties for peace of mind.
Why Dolphin Sigma?
Three Commercial Motors
The Dolphin Sigma utilizes three commercial motors that are more powerful and more reliable. These ProLine™ exclusive motors take the pool cleaning to a new level.
NanoFilters™
Take your pool water to the next level with NanoFiltration™. These filters are able to capture what other robots miss. With an included NanoFilter™ set, experience the increased performance of the ProLine™.
Gyroscope & Wi‑Fi
The Dolphin Sigma uses advanced technology with gyroscope sensors and Wi-Fi, enabling precise cleaning with SmartNav 3.0™. Connect and control your Sigma from anywhere via the app to schedule and manage your pool cleaning.
No Restocking Fee & 30 day trial
Experience the Dolphin Sigma in your own pool for 30 days. With no restocking fees and a 50% longer 3 year warranty, feel confident in buying the Dolphin Sigma. Try our most advanced robotic pool cleaner yet in your own pool today.
Owner reviews
Rated 4.9 out of 5 by pool owners.
2,189 ratings
Our most high-tech ProLine™ robot, with three commercial motors and app control. Here is what Sigma owners say.
“It's expensive but worth it! When you use the ultra fine filter it picks up every speck of dirt. The app works great and I have no regrets buying the Sigma.”ThomasVerified buyer
“So easy! Just put it in the pool, press the power button and it cleans the pool spotless... Worth the extra money for this model.”J. M.Verified buyer
“Thrilled to have replaced our $200-a-month pool guy... We've been using 'Bob' for over a month and he's the best!”AnnaVerified purchase, Amazon
“It's a beast! Lots of windy days with fine sand getting blown into the pool. This little guy with the fine filters went to work.”Amazon customerVerified purchase, Amazon
“Does exactly what it says it does. Saves so much time, and that's more time for fun.”Diana B.Verified buyer
INTRODUCING THE NEW 2026 SIGMA
Our Most High-Tech Robot Yet.
Experience ProLine™ performance combined with unparalleled technology. With an onboard gyroscope, three powerful commercial-grade motors, quad brush design, and the myDolphin Plus app, experience the most advanced Dolphin pool robot ever made.
What's Included
With a plug and play design, all you need to get started is a standard outlet. Simply plug the Dolphin Sigma in and it gets to work. Everything you need to get started is included in the box.
Dolphin Sigma
NanoFilters™
Standard Filters
Power Supply with myDolphinPlus
55ft Cord with Anti‑Tangle Swivel
Manual + 3‑Year Warranty
TOP OF THE LINE
The Top ProLine™ Robot
The ultimate Dolphin pool robot. The Dolphin Sigma is our best robotic pool cleaner yet. Sigma combines all the advanced features you expect from a Dolphin ProLine™ pool robot and so much more.
Meet Sigma, the pinnacle of ProLine™ innovation. Experience the Dolphin Sigma in your pool for 30 days. Enjoy no restocking fees and free shipping. Discover the ProLine™ difference today.
MORE ADVANCED.
Gyroscope Precision
Experience unparalleled precision with Dolphin Sigma's gyroscope technology. This innovative feature allows the Sigma to navigate your pool with pinpoint accuracy, ensuring every corner is covered. The gyroscope maintains balance and direction, preventing any missed spots and delivering a thorough clean every time.
GEN-2 FILTERS
NanoFiltration™
Embrace crystal-clear water with Dolphin Sigma’s NanoFilters. These high-tech NanoFilters capture the smallest debris and particles, ensuring your pool water is as clean as it is inviting. Say goodbye to cloudy water and hello to a pristine swimming experience with the power of NanoFilters.
THE ULTIMATE POOL FILTER
NanoFiltration
Experience a new level of clean. Crystal-clear water has never been easier. Powered by three commercial-grade motors and NanoFiltration™, the Dolphin Sigma unlocks a deeper clean. Through a process called sieving, these high-spun polyester filters are engineered to clean deeper than standard Dolphin mesh filters. Allowing you to get back to what is important, enjoying your pool.
FROM THE FLOORS TO THE WATERLINE
Waterline Cleaning Pro
Enjoy spotless pool edges with Dolphin Sigma's waterline cleaning feature. This innovative function targets the waterline, scrubbing away dirt and oils that accumulate at the surface. Maintain a pristine pool from top to bottom with effective waterline cleaning.
Dolphin Sigma’s HyperGrip tracks provide superior traction on all pool surfaces, ensuring efficient cleaning and excellent climbing ability. These tracks grip firmly, allowing the Sigma to maneuver easily and clean thoroughly, even on vertical surfaces.
THREE MOTORS. ONE ROBOT.
Triple Commercial-Grade Motors
The Dolphin Sigma uses three commercial-grade motors for enhanced power and efficiency. Taken from the Dolphin Wave Commercial lineup, the Dolphin Sigma brings commercial power at a lower cost with more features for residential pools. These powerful motors work in harmony to provide superior suction and maneuverability, tackling even the most stubborn dirt and debris. Enjoy a spotless pool with the unmatched cleaning performance of triple motors.
Benefit from continuous cleaning with Dolphin Sigma's efficient power management. Spend more time enjoying your pool and less time worrying about recharging, thanks to the Sigma’s enduring performance and reliable energy use.
SCRUB AND VACUUM LIKE NEVER BEFORE
Quad Scrubbing Brushes
Achieve a deeper clean with Dolphin Sigma's quad brushes. Designed to scrub and agitate dirt and algae from every surface, these four powerful brushes ensure no grime is left behind. Your pool walls and floor will shine with the comprehensive cleaning action of quad brushes.
A STEP ABOVE
SmartNav 3.0™ Scanning
Unlock intelligent pool cleaning with SmartNav 3.0. This advanced navigation system scans and maps your pool, optimizing the cleaning path for maximum efficiency. Ensure every inch of your pool is covered with the smart, precise cleaning of SmartNav 3.0™.
WITH A PRESS OF A BUTTON
Always Connected with Wi-Fi
Stay connected with Dolphin Sigma’s Wi-Fi capability. Effortlessly control and monitor your pool cleaner from anywhere using your smartphone or tablet. Schedule cleanings, check status, and receive updates with the convenience of Wi-Fi connectivity.
MYDOLPHIN PLUS APP
"Hey Siri, Clean my Pool"
Take pool maintenance to the next level with the MyDolphin Plus app. This intuitive app allows you to customize cleaning schedules, choose cleaning modes, and receive real-time notifications. Manage your Dolphin Sigma with ease and precision through the MyDolphin Plus app.
With voice command, tell Siri "Hey Siri, Clean my pool" and your Sigma gets to work. With a customizable scheduler, manual control, cleaning history, and more, the Dolphin Sigma unlocks a plethora of features not seen before in any other pool robot.
PATENTED TECHNOLOGY
360 Anti-Tangle Swivel
Experience seamless cleaning with Dolphin Sigma’s Anti-Tangle Swivel. This innovative feature prevents the cable from tangling, ensuring uninterrupted operation and ease of use. Enjoy hassle-free pool cleaning with the reliable anti-tangle swivel.
30 DAY TRIAL
3 Year Warranty & 30 Day Trial
With a longer 3-year warranty and 30 day trial, try the Dolphin Sigma in your own pool. Our commitment to quality ensures your robotic pool cleaner is built to last. If you're not completely satisfied, return it within 30 days. Enjoy full peace of mind with a 50% longer 3 year warranty and 30 day trial.
Tech specs
Dolphin Sigma specifications.
- 4,500gallons per hour of suction
- 3commercial-grade motors
- 4scrubbing brushes
- 3 yrno-nonsense warranty
Pool
- Pool type
- In-ground pools up to 50 ft
- Surfaces
- Concrete, plaster, gunite, pebble, tile, vinyl liner, fiberglass
- Shapes
- Rectangle, oval and freeform pools
- Obstacles
- Steps, ladders, drain covers, ledges and pop-up heads
Cleaning
- Coverage
- Floor, walls and waterline
- Cleaning cycle
- 2.5 hours
- Scrubbing
- Quad scrubbing brushes
- Navigation
- SmartNav 3.0™ scanning with an onboard gyroscope
- Traction
- HyperGrip™ tracks
- Cleaning modes
- Standard and Quick Clean
Filtration
- System
- NanoFiltration™: high-spun polyester filters that sieve rather than screen
- Included media
- NanoFilters™ and standard filter cartridges
- Full-filter alert
- In the myDolphin™ Plus app
Power
- Motors
- Three commercial-grade ProLine™ motors from the Dolphin Wave commercial line
- Flow rate
- 4,500 gallons per hour
- Power supply
- Wi-Fi power supply with a weekly scheduler by day and time
- App control
- myDolphin™ Plus over Wi-Fi and Bluetooth, with Siri voice control
- Cable
- 55 ft with patented 360° anti-tangle swivel
- Operation
- Corded: always cleaning, never charging. Plugs into a standard outlet.
- Assembly
- None required. Plug the power supply into a standard outlet and drop the robot in the pool
Size and weight
- Robot weight
- 24.6 lb
- Box dimensions
- 23.0 × 19.1 × 13.8 in
- Shipping weight
- 40.8 lb
- Part number
- 99991036-SPLI
Warranty and trial
- Warranty
- 3 years, not prorated and not limited by cycles
- Trial
- 30-day in-pool trial with no restocking fee
- Shipping
- Free 1-3 day FedEx shipping
Support
Dolphin Sigma support.
Manuals to download, answers to the questions we hear most, and a Dolphin specialist on chat whenever you need one.
Owner's Manual
Operating instructions, filter care, storage and troubleshooting for the Sigma.
Download
Quick Start Guide
Up and running in minutes: first cycle, the filter and the power supply.
Download
Talk to a specialist
Live chat with a Dolphin pool cleaner specialist about your pool, filters or set-up.
Start a chat
3-year warranty
Not prorated and not limited by cycles, with a 30-day trial and no restocking fee.
Warranty details
Questions about the Sigma
What makes the Sigma different from the Premier?
Both are ProLine™ robots with commercial-grade motors, NanoFiltration™, waterline cleaning and a 3-year warranty. The Sigma adds a third motor, a gyroscope for SmartNav 3.0™, four scrubbing brushes and the myDolphin™ Plus app. The Premier is the only Dolphin with Multi-Media™ and a leaf bag. Compare them side by side.
Does the Sigma need Wi-Fi?
No. Press the power button and it cleans. Wi-Fi and the myDolphin™ Plus app add the weekly scheduler, manual control, cleaning modes, cleaning history and notifications, and you can even say "Hey Siri, clean my pool."
Does it clean the waterline?
Yes. Three commercial motors and HyperGrip™ tracks climb every wall, and the quad brushes scrub the tile line. SmartNav 3.0™ and the gyroscope keep it on course so the floor, walls and waterline are covered in about 2.5 hours.
Which filters are included?
Two sets: NanoFilters™ for fine debris like sand, silt and algae, and standard cartridges for everyday cleaning. There is no leaf bag on the Sigma; if leaves are your main problem, look at the Premier.
Will it work in my pool?
The Sigma is built for in-ground pools up to 50 ft in any shape and on every surface, with steps, ladders, drain covers and ledges. Not sure? Ask a Dolphin specialist before you buy.
What does the 3-year warranty cover?
Maytronics warrants the robot against defects in materials and workmanship for 3 years. It is not prorated and not limited by the number of cycles. Service is available through 1,200+ Dolphin dealers. Read the full warranty.
What if it isn't right for my pool?
Try it in your own pool for 30 days. If it isn't right, return it with no restocking fee; you pay to ship the original product back. If you exchange it for another model, we'll ship the replacement free. See the return policy.
Compare
Which Dolphin is right for you?
Put any two Dolphin robots next to the Sigma. Pick a model in each column.
ProLine™
Series
Floor, walls and waterline
Cleans
Ultra-fine and standard cartridge sets
Filtration
4,500 GPH
Suction
2.5 hours
Cleaning cycle
4
Scrubbing brushes
SmartNav 3.0™ with gyroscope
Navigation
Yes
Weekly timer
myDolphin Plus (Wi-Fi and Bluetooth)
App control
55 ft
Cable
Yes
Anti-tangle swivel
3 years
Warranty
Up to 50 ft
Pool size
ProLine™
Series
Floor, walls and waterline
Cleans
Multi-Media™: NanoFilters™, leaf bag and standard filters
Filtration
4,500 GPH
Suction
3 hours
Cleaning cycle
2
Scrubbing brushes
SmartNav 2.0™
Navigation
Yes
Weekly timer
No. All controls on the power supply
App control
55 ft
Cable
Yes
Anti-tangle swivel
3 years
Warranty
Up to 50 ft
Pool size
ProLine™ and Max-Series™
Series
Floor, walls, waterline, sun shelves and stairs
Cleans
XXL MaxBin™ basket with NanoFilter™ panels
Filtration
4,000 GPH
Suction
2 hours
Cleaning cycle
2 HyperBrushes™
Scrubbing brushes
SmartNav 2.0™
Navigation
Yes
Weekly timer
myDolphin Plus (Wi-Fi and Bluetooth)
App control
55 ft
Cable
Yes
Anti-tangle swivel
2 years
Warranty
Up to 50 ft
Pool size
Complete your setup
Optional Accessories
Add a caddy and a caddy cover for your Dolphin Sigma to make transporting, storing and protecting it even easier.
Dolphin Universal Caddy
$145
A sturdy, smooth-rolling cart that holds your robot, its cable and the power supply in one place. Wheel it from storage to poolside in seconds and keep it off the ground between cleanings.
Dolphin Premium Caddy Cover
$99
A heavy-duty, water-resistant cover that fits over the caddy with your robot stored on it, shielding both from sun, rain and dust so it is always ready to clean.
Where to Buy
Buy from us or shop all Authorized Dolphin Dealers and buy your Open Box Dolphin Sigma Robotic Pool Cleaner today.
Certified Open Box
Open Box Dolphin Sigma Robotic Pool Cleaner
$2999 $2299 SALE Save $700
Save hundreds on a Certified Open Box Dolphin Sigma robotic pool cleaner. With gyroscope, NanoFilters, and 3 year warranty, try for 30 days.
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