Some 700 members of the PCS civil service workers' union at the Maritime and Coastguard Agency (MCA) struck for 48 hours over the bank holiday weekend as part of their long running fight for decent pay.
This latest action follows five days of strikes against the government's below inflation pay rises.
The workers are demanding that they are paid the same as staff at other emergency services.
Starting salaries at the MCA are currently a measly £12,509 a year.
Mark Serwotka, PCS general secretary, said, 'Strike action is a last resort for our members who provide an invaluable service in ensuring the safety of shipping in British waters.
'The latest action could have been avoided if the government and the MCA hadn't continued with their refusal to negotiate a satisfactory outcome.'