The Best Robot Lawn Mowers Without Boundary Wire (2026)

The right mower depends less on brand than on your lawn: size, slope, shade and how it is broken up by fences, beds and hardscape. The criteria below are in the order that usually decides the purchase.

01Lawn size, run time and coverage speed

Manufacturer ratings assume the mower runs several days a week on a reasonably open lawn; our picks run from 1/8 acre (i105N) to 1.25 acres (LUBA 3 AWD 5000).

Run time shows how the rating was earned: about 60 minutes for the i105N on a 2.55 Ah pack, about 110 for the X430 on 12.8 Ah per Lawn Care Guides, and up to 215 for the LUBA on 15 Ah (Gardobot measured closer to 180). Worx publishes no run time for the WR320. The X430 and LUBA both quote roughly 5,400 sq ft per hour, so they cover an acre in a few sessions while the 7.1 in i105N needs most of the week for a fraction of that.

Buy one size class up if the lawn is split into several zones, has many obstacles, or you want to mow only two or three days a week.

02Navigation: how RTK, LiDAR and vision cope with trees and fences

All four mowers use RTK, satellite positioning with correction data that brings accuracy down to a few centimeters. The differences are where the corrections come from and what happens when the sky is blocked.

The i105N ships with an RTK antenna on a stake that Top Ten Reviews says must sit more than 2 m from buildings under open sky. The X430, WR320 and LUBA 3 receive network RTK over the internet, so there is nothing to mount; Bob Vila and PCWorld both ran the X430 without touching its included antenna.

Under tree canopy or beside a tall fence, satellites drop out, and the fallback sensor takes over. The i105N and WR320 use visual SLAM from cameras; the X430 adds 360-degree cameras and visual-inertial odometry; the LUBA 3 adds a 360-degree LiDAR that maps the surroundings and needs neither light nor sky. EasyLawnMowing found the LUBA held its course under dense trees, Robot Review Desk credits the WR320's V-SLAM with staying oriented in shade, and MowScout tells i105N buyers with heavy tree cover to look elsewhere. Solid fences cause the same problem on a narrow side strip: PCWorld watched the X430 hold a raised edge that a smaller Navimow had slipped off, while i105N owner reports collected by Bikman Tech mention weak signal.

The dock is part of the navigation system. How-To Geek moved the X430's station three times to find sky, and Top Ten Reviews learned the i105N's dock has to sit on perfectly level ground.

03Slope rating and drive

The two-wheel-drive mowers, the i105N and WR320, are rated to 30 percent (17 degrees). The all-wheel-drive X430 is rated to 84 percent (40 degrees) and the LUBA 3 to 80 percent (38.6 degrees). Ratings assume dry grass; Bob Vila's tester watched the WR320 lose traction in thick St. Augustine along edges, so give a two-wheel-drive mower some margin.

All-wheel drive has costs. The X430 weighs 63.7 lb and the LUBA 41 lb, against 24 lb for the i105N and 31 lb for the WR320. Reviewed also found the LUBA 3 AWD could scalp turf and dig divots on tight turns, a known habit of aggressive tires on soft ground.

04Cutting width and height range

Width sets speed: 7.1 in (i105N), 8.7 in (WR320), 15.7 in (LUBA, two discs) and 17 in (X430, two discs with 12 blades). Height range sets which grasses you can keep. The X430 covers 0.75 to 4 in with electric adjustment, the WR320 1.57 to 3.54 in electric, the US i105N 2.0 to 3.6 in manual. The LUBA comes in two non-overlapping versions, 1.0 to 2.7 in or 2.2 to 4.0 in, so decide your cut height before you pick the variant. If you keep tall fescue at 3.5 in or more, only the X430 and the LUBA 5000H qualify.

None of them replace a string trimmer. Segway says the X430 trims to within 2 in of edges; Robot Review Desk and Lawn Craft Supply report the WR320 leaves a strip along hard borders; Specslib notes the LUBA leaves a ring around trunks and corners.

05Obstacle detection and noise

All four recognize objects with cameras before contact. Segway lists more than 150 object types for the i105N and more than 200 for the X430, which adds time-of-flight sensors; Mammotion claims more than 300 for the LUBA, with LiDAR backing the cameras; Worx instead treats anything that is not grass or leaves as an obstacle. Cameras need light: How-To Geek saw the X430 miss spots on night runs, so schedule daytime mowing.

Noise separates the small mowers from the big ones. The i105N is rated at 58 dB(A). Spec listings for the X430 give up to 68 dB(A), though PCWorld lists 60. Mammotion publishes no figure for the LUBA and third-party listings range from 64 to 70 dB(A); Worx publishes none for the WR320.

06Hidden costs: RTK and 4G fees, blades, antenna, garage

Network RTK is free for the life of the mower on the X430, WR320 and LUBA 3. Cellular data is the variable: Worx includes it for life, Mammotion for three years, and Segway for one year on the X430, after which PCWorld and Residential Tech Today report a paid annual plan. The i105N needs no data plan, only the staked antenna cabled to its dock.

Blades are consumables: three on the i105N and WR320 (Worx includes eight spare kits), 12 on the LUBA and X430, replaced each season on a large lawn. A garage is optional on all four; Segway sells the X430 bundled with one, and the LUBA garage is a separate listing.