The head of water safety for the RNLI said he fears the “tragedy will continue” after a series of deaths recently.
Gareth Morrison said the lifeboat service has seen their busiest period “for many years” and described this year as being one of the worst he has seen.
Monday saw the latest death on Northern Ireland’s waters, as a man passed away after being pulled from the water at Ballintoy Harbour.
It follows eight other deaths across the island of Ireland last week.
At the weekend, Kilkeel woman Sharon Perry passed away after being recovered from the water near Kilkeel, while a man drowned in Brantry Lough in Eglish.
Mr Morrison said staycations and the warm summer weather has likely driven significant numbers of people to the coast and explained this has led to the rise in incidents.
“Unfortunately, the number of drowning tragedies is also considerably higher than normal and our lifeboat crews are busier than normal. Everything is pointing to a very busy season,” he told BBC’s Good Morning Ulster.
“There is a lot of this summer left and the fear is the tragedy will continue.
“Our coastline is beautiful and we are absolutely a nation who loves heading to the water when the sun comes out.
“The problem is a day at the coast can so easily turn into a day of tragedy. We have seen, we believe, in the region of over 40 drownings across the UK in the past two weeks.
“That is an incredibly worrying picture. That is turning from a day of fun and memories to an absolutely heart-wrenching day of tragedy. Every single one of us need to play a part here to stop that tragic trend."
Mr Morrison said people can take simple steps to protect themselves, including going to a beach that has a life-guard facility and also to always have a mobile phone on hand to contact the emergency services.
“Without scaremongering too much here, we need to really listen up and pay attention here. Certainly in living memory we are seeing, in the short period of time, the largest number of water fatalities,” he added.
“August tends to be the month that would see the largest fatalities in the island of Ireland so if we have started that trend early... we really need to do something about that.
"If you do need assistance, or even if you see someone else in trouble or if you are not sure, immediately dial 999 and if you are on the coast ask for the Coastguard and if you are inland ask for the Fire Service.”