More than 100 people have joined a rally to save a Pembrokeshire coastguard station, 15 years since the Sea Empress oil tanker disaster nearby.
Thousands have also signed a petition against against the closure of Milford Haven station.
The coastguard service head, who is visiting Wales' busiest port, called the system "fundamentally inefficient".
Campaigners say leaving Milford with no coastguard operations centre would be "dangerous" and "irresponsible".
Swansea and Southampton will provide cover for the port in future.
The petition was started by Mair Williams, a cleaner at the Milford Haven station and one of those who said the station closure plans put lives at risk.
The 52-year-old grandmother, originally from Anglesey where the Holyhead station is also earmarked for closure, said her sons and grandchildren are fishermen and she was stunned to learn of the closure plans.
"We grew up with the seas as our playground and the coastguard was something we could always rely on if anything happened to any member of our families," she said.
"There is no other coast that has got as many time bombs as Milford Haven has.
"We need our coastguard even for just peace of mind. They're there to save lives and save lives is what they do," Mrs Williams said.
Since starting the petition, she said she was amazed at the amount of people who say they have had a family member rescued.
Opponents argue that local knowledge of busy shipping areas will be lost when the stations close in 2012/13.
Dennis O'Connor, 44, from Neyland, a volunteer search and rescue and cliff rescue team member at Llansteffan for three years, said: "Local knowledge is irreplaceable.
"You cannot extend local knowledge to remote areas. It will place undue pressure on very professional staff in Southampton. They have enough to do as it is," he said.
"It could well be that coastguard search and rescue teams are sent to the completely wrong area because someone in Southampton has misheard what the caller has said.
"In a distress call situation, it is very difficult for people to get the right information anyway."
A rally was held at the bandstand at the Rath in Milford Haven from midday.
Save The Coastguard Campaign members went from there to Milford Haven coastguard station to greet Vice Admiral Sir Alan Massey, the head of the coastguard service, who is visiting the area.
The Maritime and Coastguard Agency has said operations need to be more effectively run, and Sir Alan Massey is to explain the plans to staff.
Under the proposals, the number of stations in the UK will be reduced from 18 to eight. Only three - in Aberdeen, Southampton/Portsmouth and Dover - will be open 24 hours a day.
Sir Alan told BBC Wales there was no way he would put mariners' lives at greater risk.
"What we are seeking to achieve is a better coastguard service in the 21st Century and to do that we need a national network and to make better use of the people, skills and technology so we can coordinate things to be far more efficient than we are at the moment.
"Local knowledge is a key issue and seems to be the one that captures people's imagination, but we have to be more analytical.
"We need to use our data systems more efficiently and use those who have detailed local knowledge in a better sort of way."
The protest is happening 15 years since the Sea Empress spilled 73,000 tonnes of crude oil over 120 miles of coastline after it was holed below the waterline as it entered the Cleddau Estuary.
Nick Ainger, a local MP at the time of the disaster, called the proposed cuts "absolutely appalling".
Remembering the disaster he said: "When the oil first came to Tenby, people there were standing on the esplanade and weeping.
"They thought Tenby was finished."