The machinery was being used to replace groynes as part of a scheme to protect the beach from erosion.
Bournemouth, Christchurch and Poole (BCP) Council said it tipped over in soft sand on a rising tide.
A video showed the driver climbing into the bucket of another excavator which carried him to safety. The machinery was later recovered from the sea.
Council environment cabinet member Andy Hadley posted an image on X of the half-submerged digger lying on its side.
He confirmed the driver was unhurt and had managed to isolate the fuel supply.
He said: “Oops, groyne replacement on Bournemouth Beach. Digger in the sea. Driver is OK…”
The council later said: “The excavator was successfully retrieved at low tide this afternoon using a specialist recovery team.
“The excavator was isolated, the driver safely recovered with no injuries, and there was no fuel, lubricants or hydraulic oils spilt into the sea or onto the beach.”
It added that it would be back to “business as usual” on Thursday, resuming work on replacing the timber groynes.
The work is part of a 17-year beach management scheme, which started in 2015, to help protect the coastline from flooding and erosion.
The groynes are being replaced using tropical hardwood and recycled planking, with work expected to be completed by the end of March 2024.
Source : BBC
