The National Sea Rescue Institute on Tuesday warned that drownings and capsizing of boats were most likely to occur during spring tides expected on July 1.
It was concerned that with the school holidays, children angling from rocks, boating or bathing, were at great risk of being swept out to sea, spokesman Craig Lambinon said in a statement.
Data showed that during the few days of the spring tide, particularly at river mouths and at harbour entrances, boats were at risk of capsizing.
Spring tide occurs twice a month, every month of the year, around in the world. It peaks on the day of the full moon and again on the day of the new moon, causing a higher than normal high tide and a lower than normal low tide.
The spring tides were known to cause the rip currents, which could be compounded by rough seas in winter.