Boskalis’ trailing suction hopper dredger (TSHD) Gateway is adding over a million tons of beach material onto the Southsea beaches between The Pyramids and the Coffee Cup at Eastney.
The work started on Tuesday and is being carried out round the clock for about 30 days.
After the shingle has been pumped ashore in piles, it will be moved along the beach using dumpers and moved into place using bulldozers and diggers.
Southsea Coastal Scheme said: “ The shingle comes from licensed dredging zones southeast of the Isle of Wight, selected to avoid sensitive habitats .”
“It may appear darker than normal but the beach will look the same once complete.”
The fencing is expected to remain in place until mid-to-late December.