More than 200 people have turned out for a rally in Holyhead, Anglesey, to protest against plans to close the town's coastguard station.
The proposals would see the UK's 18 coastguard stations reduced to eight to "modernise" the service.
Speakers at the protest included the town's mayor, Anglesey MP Albert Owen, and union representatives who maintain the station is one of the UK's busiest.
The Maritime and Coastguard Agency says the service must be more effective.
The Holyhead protest followed a rally last Tuesday at the Milford Haven station in Pembrokeshire, which is also under threat as the Maritime and Coastguard Agency (MCA) seeks to save £210m over 25 years.
Under the plans, Wales will have daytime cover from stations in Swansea, Belfast or Liverpool.
Night-time cover will be handed over to specialised maritime operation control rooms (MOC) in Aberdeen, Southampton and Dover.
The Public and Commercial Services Union said such measures would not be adequate in offering a high standard of cover along the 300 miles of north Wales coast.
Union representative Ray Carson, a coastguard watch manager, said: "The whole thing is ill-conceived.
Demonstrators march against the closure of Holyhead coastguard station
"Holyhead is consistently in the top six busiest stations in the UK, and one of the great concerns we have is the local knowledge aspect."
He gave an example of a group of children who called 999 to assist a friend in trouble in the sea.
They did not know where they were in north Wales, but after a few minutes of questioning, a Holyhead coastguard with detailed knowledge of the coastline was able to accurately guess their location.
It's a small cost to pay to keep our coastlines and seas safe
Albert Owen, Anglesey MP
He also had doubts about the computer systems in the maritime operation control rooms.
"It doesn't take things like estuaries into account, so not understanding somewhere like the Mawddach could add an extra hour to an emergency response team's journey," he said.
Mr Owen said the closure plan was "an attack on maritime communities across Wales".
He said the MCA's consultation on the scheme was flawed and should be suspended until after the Transport select committee had completed an inquiry.
He said: "This is about safety, safety first. It's a small cost to pay to keep our coastlines and seas safe so that people can enjoy them and trade can use them.
"These people are an important link in that. Anglesey has a huge tradition of search and rescue."
Protesters marched in Pontypridd in opposition to RCT council proposals
Earlier this week, MCA chief Sir Alan Massey visited Mr Carson and his colleagues at Holyhead.
He told them: "We must not jeopardise the safety of those at sea or on the coast".
Sir Alan said having teams of coastguards using their skills on a more regular basis to those in the smaller stations would lead to an enhanced service.
He said assistance would be sought from local volunteer coastguards, RNLI crews and harbour masters to ensure access to local knowledge.
The MCA said it would welcome any input from local people.
A spokesperson for the MCA said: "We are currently consulting about our proposals to modernise the coastguard service.
"Local knowledge is one of the topics being raised at the moment. Comments received through this consultation process will be reviewed after the consultation closes on 24 March.
"We welcome responses from all members of the community, and to make sure we hear from the community we will be holding a public meeting on Wednesday, 2 March at Holyhead High School."
• Elsewhere, the Unison union organised a protest and rally in Pontypridd on Saturday for Rhondda Cynon Taf workers against cuts they said were imposed on them by the Labour-controlled council.
Unison has criticised proposals which it says downgrade pay and conditions, but council leaders have said the alternative is "job losses and service cuts".
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