Police say thieves at south coast ports are still targeting Guernsey and Jersey cars waiting for the ferry back.
The warning has been issued by Guernsey Police but equally applies to Jersey residents.
Earlier this year, there was a spate of thefts from island registered cars waiting for the ferry in Poole.
As the summer holidays get underway and vehicle traffic on the ferries increases, Police advise:
- Ensuring the car is locked
- Parking up near a place with obvious CCTV and ideally lights if stopping at night
- If possible, leaving all valuables in a hotel room
- Hide any valuables kept within the car
- Do not leave items like charging leads in view, as these can entice thieves
Police say thieves at south coast ports are opportunists and taking these simple steps denies them the opportunity to steal.

Guernsey castle to host 150 performers
Trial of man accused of Sarah Groves' murder could resume
Corridor gallery opens in Guernsey hospital
Guernsey Prison Governor to 'step aside' during conduct investigation
Guernsey reservoir walk reopens following 'extensive' tree surgery
Two more Asian Hornets found in the Bailiwick of Guernsey
Guernsey Autism charity gets States commissioning deal
Digital travel permissions extended to Channel Islands this month