A number of orange lifebuoys have been found to have been 'deliberately' thrown into the water.
Jersey Coastguard say misuse of the devices is could have fatal consequences, if they aren't available in an emergency.
Coastguard and VTS Manager Dan Downey wants anyone who is throwing the buoys in the water to 'think again'.
"Discarding a lifebuoy into the harbour when it isn’t needed is vandalism and could cause death or life-threatening injury if the equipment is then not available when it’s really needed by someone who’s in trouble in the water."
There are 128 'strategically placed' flotation rings around the island's coast, which are designed to be thrown in the water for someone in distress.
Islanders are asked to report any damaged or missing life buoys to the Coastguard on 01534 447705.

Wind farm progress paused over export uncertainty
Direct flights from Jersey to Southend revived
Electricity prices to rise by 2.5%
Jersey's community comes together to reimagine the Occupation Tapestry
Government attempts to reframe Havre des Pas Lido proposal ahead of debate
Aurigny extends flight schedule up until early January
Blue Islands debt 'simply a cost of the pandemic'
£3.5m in grants to switch to greener heating systems