Authorities in Quang Ninh, home to Ha Long Bay, said more than 4,100 fishing boats and nearly 500 tourist vessels had been recalled to secure anchorages, while 7,900 aquaculture farms, including 800 offshore sites, were reinforced and workers moved ashore.
Over 3,000 officers and soldiers with hundreds of vehicles have been mobilized for rescue readiness.
Provincial chairman Bui Van Khang said the priority is preventing casualties and minimizing damage.
Hung Yen imposed the same noon sea ban on Wednesday, aiming to finish recalling its 1,063 vessels and relocating aquaculture workers in low-lying riverside and coastal zones by 6 p.m. The province reported most boats already anchored safely, with remaining craft maintaining constant contact with families and authorities.
In major port city Hai Phong, officials had not announced a sea ban, but all 114 wards, communes, and special zones held emergency meetings, with directives to secure communications and ensure stable power during the storm response.
The national weather service said that on Wednesday afternoon Ragasa's center was about 500 km off Mong Cai of Quang Minh, with maximum sustained winds of 150–166 kph, weaker than in the morning.
The storm was moving west-northwest at around 20 kph and is forecast to make landfall in Quang Ninh by midday Thursday, with sustained winds of 60–88 kph, gusting up to 100 kph.
Ragasa struck Taiwan and northern Philippines on Tuesday as a super typhoon, bringing floods and destructive winds that killed at least 14 people and left 24 missing. Millions in Hong Kong, Macao and Shenzhen have been evacuated or told to stay indoors as southern China braces for impact.