Firefighters were called on Saturday to reports of grassland on fire near Castlerock Beach just before 5pm.
A Northern Ireland Fire & Rescue Service spokesperson said:
“Northern Ireland Fire & Rescue Service (NIFRS) received a call at 4:55pm to a report of a fire at the Sea Road area of Castlerock on Saturday 14th May.
“One Fire Appliance from Coleraine Fire Station was deployed to the scene of a quantity of grassland on fire in the area. Firefighters using 2 hosereel jets dealt with the fire, which was adjacent to the beach.
“Northern Ireland Fire & Rescue Service finished at the scene at 5:26pm and the fire is being treated as deliberate.”