Two people men have been trying car doors in Argyll Road, North Shore, this week, police said.
"On one occasion they managed to get into an unlocked car," a spokesman said.
"Wherever you are in Blackpool, please don't make it easy for them.
"Always keep your car locked and never leave valuables inside, even in a closed glove compartment."
Officers released CCTV footage of two men they want to speak to.
If you recognise them, you can call police on 101, or email firstname.lastname@example.org