Lough Swilly RNLI took to Facebook to show that yet another ring buoy is missing, this time in Swan Park.
The voluntary group have urged that it needs to stop.
It comes as another ring buoy went missing at the diving boards on the shore front at the beginning of the month.
While 3 ring buoys had gone missing from Inch pier at Inch island at the end of April.
The RNLI have advised the public to notify Gardaí or Water Safety Ireland if you ever notice that a ring buoy is missing from its stand or if you observe any incidents involving the misuse/theft of any type of safety equipment.