Following weeks of intensive training in preparation for the new season, the lifeguards will be keeping visitors safe on seven beaches along the Causeway Coast and three in Co Down.
The beaches include Benone, Downhill, Castlerock, Portstewart Strand, Portrush West, Portrush East, Whiterocks, Tyrella, Murlough and Cranfield.
Five of the busier beaches had lifeguard cover during the Easter period which was followed by a weekend patrol on six beaches throughout April, May and June.
During weekend patrol on Sunday 14 June, RNLI lifeguards on Portstewart Strand dealt with their first major first aid incident of the summer.
At around 4.30pm, lifeguard Mairead McKeague was on duty at the water’s edge and patrolling the area between the red and yellow flags when she spotted a teenage boy at the east of the beach who had slipped on rocks and hit his head.
McKeague alerted senior lifeguard Damian McCauley and lifeguard Clara Doran, who responded immediately while she maintained patrol of the beach.
Lifeguard James Shannon, meanwhile, acted as the communications liaison between the RNLI and their colleagues in the coastguard and Northern Ireland Ambulance Service who also responded.
On scene within five minutes, McCauley and Doran proceeded to carry out first aid and treat the casualty for a head wound. They were joined five minutes later by a NIAS Rapid Response Paramedic and the Coleraine Coastguard Rescue Team, who proceeded to transport the casualty to their vehicle.
Speaking following the incident, RNLI lifeguard supervisor Tim Doran said: "Our lifeguards worked well together, spotting the incident quickly, communicating with each other and reacting swiftly to administer first aid to the casualty.
"They used their lifeguard training and skills to good effect with this incident serving as an example of the vigilant work our lifeguards do in responding to events that happen on the beach as well as those that occur in the water."
From Saturday 20 June, the RNLI took up full-time daily duty on all 10 beaches continuing to Sunday 6 September, when weekend duty will then resume on selected beaches throughout September.
Lifeguards will be on the beach daily between 11am and 7pm on the Causeway Coast and between 10am and 6pm in Co Down.
Ahead of the new season, the RNLI has reminded visitors to the beach to ask the lifeguards for water safety advice, and to call on a lifeguard if they see anyone in difficulty.
RNLI lifeguard manager Mike Grocott also encouraged visitors to bear in mind some key safety messages.
"The RNLI’s advice for anyone planning a trip to the beach is to check weather and tide times before you go and if planning to go into the water, swim at a lifeguarded beach, between the red and yellow flags.
"Avoid using inflatables in strong winds or rough seas. If you get into trouble, stick your hand in the air and shout for help and if you see someone else in trouble, tell a lifeguard. If you can’t see a lifeguard, call 909 or 112 and ask for the coastguard."
Throughout the summer, the lifeguards will deal with a range of incidents.
"While the same safety advice applies to all our beaches, we do tend to see patterns of activity that are more specific to some beaches than others," said Grocott.
"Whiterocks, for example, is most affected by last winter’s storm damage and there is a lot of coastal erosion there. It is also a beach known for its waves and swells so it is popular with surfers and body boarders.
"Benone, Portstewart and Portrush East, meanwhile, are large beaches which we know will attract a lot of people throughout the summer. We can also expect to be exceptionally busy on vank holiday weekends, during the fortnight holiday period in July and if and when the weather peaks.
"Having a good knowledge of the profile of our beaches and the types of activities that are popular on each of them helps to guide how we carry out our lifeguard training before the season begins so our lifeguards can be prepared for all the incidents they will encounter."