Detectives are appealing for information following the thefts in the early hours of today (Tuesday, April 19).
On both occasions, a blue BMW was reported stolen.
The first theft was reported from the Drumnacanvy Road area at around 2.45am.
The second was from the Lisnagrilly Manor area overnight - again, a blue BMW car was taken in what police are treating as a keyless car theft.
Detective Sergeant Dave Stewart said: “Enquiries are continuing and police would appeal to anyone with any information or who may have dashcam footage that may feature one or both of these vehicles to contact us on 101, quoting reference number 536-190422.
“Alternatively, you can submit a report online using the non-emergency reporting form via www.psni.police.uk/makeareport/
“You can also contact Crimestoppers anonymously on 0800 555 111 or online at www.crimestoppers-uk.org/”
The car thefts have prompted the poice to warn others to take some steps to help the security of their vehicles.
“We are urging vehicle owners to be vigilant, especially those with keyless entry cars,” said Det Sergeant Stewart.
“With advances in technology, thieves are now able to gain access to your vehicle by redirecting the wireless signal from your key fob.
“Motor vehicles are extremely expensive, and owners should take the same precautions as they do with home security.
“Where possible, keep your car in a garage or lock your driveway gates.
“£stablish a routine to help keep your vehicle safe, including using your garage if available to secure your vehicle.
“Use physical car locks such as steering column locks and chains, as well as keeping all car keys (including spares) away from exterior doors and walls.
“Motorists are also advised to use a blocking pouch also called a Faraday pouch (lined with metallic material) to help block the wireless signal from your key fob.”