Work is to be carried out at Downhill beach, Portrush Harbour and Portballintrae Harbour.
The work, costing in the region of £250,000 will be completed before the start of the summer season.
At Downhill, work will be carried out to prevent flooding at the entrance to the beach from the adjacent river.
The work will cost £67,720.
Over £81,000 will be spent at Portrush Harbour to repair steps and the harbour wall.
In Portballintrae over £101,000 will be spent on the quay, which is a historical monument.
In further planned improvements, Council submitted a grant funding application to the European Fisheries Fund in a bid to improve the commercial fishing infrastructure at Portrush and Portstewart Harbours.
They were granted over £181,000.
At last Tuesday night’s meeting, members agreed to proceed with the improvements, which will include a CCTV system at both harbours, an ice room facility at Portrush and an automatic barrier at Portstewart.
At Portrush Harbour quayside lighting will be installed.
And, at Portstewart Harbour, wall repairs will also be carried out.
Members agreed to proceed to the next stage of the process, which will produce the final business case and tender for the work at both sites.