What it is
The Sunseeker S4 is a wire-free robot mower that navigates with automotive-style 3D LiDAR fused with AllSense Vision AI, running on a 10 TOPS chip. Sunseeker sells it on its official US store, shopsunseekertech.com. This listing is Shopify product 10220181815613, variant 51334659866941, SKU SKRMS4.
Unlike Sunseeker’s X-series, the S4 uses no RTK base station and doesn’t need a clear view of the sky. It scans its surroundings to build a 3D map. Sunseeker says this keeps it accurate under dense tree canopy, in shade and beside tall structures, and lets it work at night. The LiDAR covers 360° horizontally and 70° vertically.
Setup: No perimeter wire and nothing to mount on the roof. You map the yard by walking the S4 around it in the app.
In the box (from the US page’s “What’s in The Box” section): the S4, a charging station, a charger, blades and screws, nails, a protective cover and towel, and a cleaning brush.
Who it’s for
Owners of lawns up to a quarter acre (10,890 ft² maximum mapping area) with trees, flower beds, narrow passages, shade or several zones. Sunseeker’s own “best for” line describes medium, complex yards. The S4 fits through 31.5 in (80 cm) gaps and handles up to 100 zones across 5 maps, which suits front and back lawns joined by a side path.
Check these limits from Sunseeker’s FAQ before buying:
- It is not compatible with Zoysia or St. Augustine grass.
- Grass must be under 3.5 in when it starts.
- Slopes must be under 42% (22°).
- LiDAR needs reference objects around the yard. With references on all four sides, no single run can exceed about 50 m. With only two sides, the limit is 25 m and the references must be taller than 2.5 m. A yard with a reference on only one side is unsuitable.
- It can’t mow in rain or fog. The rain sensor sends it back to the dock.
Standout details
- Coverage: Up to 0.25 acre (10,890 ft² maximum mapping area).
- Navigation: 360° 3D LiDAR plus Vision AI, with no wire and no RTK base. It mows systematic routes, can run at night, and has 3D obstacle avoidance.
- Slope and drive: 42% (22°), rear-wheel drive. Some customer quotes on the page say “all-wheel drive”, but the spec table says rear-wheel drive.
- Cut: 7 in width from a single floating cutting disc. Height is 1.6–3.2 in, per the cutting-deck image in the official US gallery. A separate trimming micro-blade deck cuts as close as 1.2 in to edges.
- Runtime (FAQ): 90 minutes of mowing per charge, 80 minutes to charge, and about 187 m²/h under test conditions.
- Support: 2-year warranty. The page offers 30-day returns, but the return policy says that applies only to unopened mowers. After opening, only faulty or incorrect units qualify.
- Not published on the US page: weight, noise, battery capacity and ingress (IP) rating. They are left out rather than taken from other sources.
Page conflicts: The FAQ still says the centrally mounted blade leaves 110 mm (about 4.3 in) uncut at the housing edge. The feature section says the micro-blade edge deck cuts to 1.2 in. The cost calculator gives an S4 “MSRP” of $1,799, while the compare-at price is $1,799.99.
Sources: Sunseeker S4 US product page, including the headline specs, feature copy, comparison table, FAQ, “What’s in The Box” section and gallery images, plus product.js and a guest cart/add.js on that store, all checked 13 Oct 2026 (AWST).
Honest verdict
For a shaded, cluttered quarter acre, the S4 is the cheapest true 3D-LiDAR option we list at $999.99. The ecovacs-goat-o1000-lidar-pro costs $1,499.99. The mova-lidax-ultra-1000 is $999 (16 Oct 2026; it was $899) and rated for 45%. The dreame-a3-awd-1000 adds AWD and an 80% rating for $1,399.99 (16 Oct 2026; it was $1,599.99). If your yard has open sky and steeper ground, Sunseeker’s sunseeker-x5 uses RTK + vision with AWD for $1,399.99.
The limits are real. The 7 in cut is narrow, the S4 is rear-wheel drive and rated for 42%, and it can’t mow in rain or fog. Warm-season Zoysia and St. Augustine lawns are excluded, and open yards without fences or trees don’t suit LiDAR. Returns are limited once the box is opened. Buy it if your lawn is a fenced or tree-lined quarter acre of cool-season grass. Otherwise, look at the Mova for a lower price or the Dreame for hills.
