Great Yarmouth's coastguard centre, which covers the Lincolnshire coastline, has closed as part of the Maritime and Coastguard Agency programme of modernisation
The agency said full operational responsibility had been transferred to Humber coastguard.
It said there would be no reduction in crews, lifeboats or helicopters. The MCA added no compulsory redundancies have occurred out of Yarmouth's 25 staff.
Chief coastguard Peter Dymond said: "Safety is our top priority and I am confident the same high-quality search-and-rescue service will be maintained throughout.
"There will be no reduction in front-line rescue resources. The availability of lifeboats, rescue helicopters, Coastguard Rescue Teams and other rescue facilities in the area will be unaffected.
Humber coastguard will begin covering the coast right down to Suffolk from tonight. It's after eight coastguard centres were closed as part of a Government cost-cutting scheme.
The Coastguard Agency has moved to allay fears that lives will be put at risk by cost-cutting changes. The number of coastguard stations around the country is being halved, as the Government modernises the service.
As a result from next week, the Humber Coastguard will embark on one of the most challenging periods in its history, but say safety remains the top priority. And frontline teams are unaffected. Tina Gelder reports.
A five-year old girl has had to be rescued after she was swept out to sea in her inflatable dinghy.
Humber Coastguard said it launched a lifeboat at Ulrome, near Bridlington, just after 1pm this afternoon.
A woman also needed medical attention after she entered the water to try to help the youngster.