The 3.5-kilometre-long Na Jomtien beach in Pattaya City is expected to fully reopen to tourists in 2025.
Construction of the 50-metre wide sand fences along the first 800-metre section of beach stretching to the south of Soi Na Jomtien 11 ended last week.
The second phase of construction has now begun and is expected to end in November 2025, said the Marine Department.
The northern section of the beach where more sand fences are being built extends to Pattaya Water Park, north of Soi Na Jomtien 11.
Starting in 2020, the erosion prevention project began after erosion had become serious enough to threaten the popular beach and tourism in the area.
Coastal erosion at Na Jomtien beach had resulted in it shrinking by about 60 rai in size between 1976 and 2015.
Pattaya ranked the eighth most popular tourist destination in the world in 2022, according to online travel booking platform Agoda.