Credit Card Skimmers: What They Are, How to Spot Them, and Where They Come From

Credit card skimming is one of the most prevalent forms of payment fraud. Despite advances in card security, skimming continues to cost businesses and consumers billions of dollars annually.

In this post, we'll explain what skimmers are, how they work, the different types, and how to protect yourself.

What Is a Credit Card Skimmer?

A skimmer is a device — often physically attached to or embedded in a legitimate card reader — that secretly captures payment card data when a card is swiped or inserted.

The captured data can then be used to clone cards or make fraudulent online purchases.

Types of Skimmers

Physical overlay skimmers attach directly over the card slot of an ATM, gas pump, or POS terminal. They're often nearly invisible.

Internal skimmers are installed inside the terminal, making them much harder to detect visually.

Shimmer devices are ultra-thin inserts placed inside chip card slots that capture data from EMV chips.

Wireless/Bluetooth skimmers transmit stolen data wirelessly to a nearby criminal — no physical retrieval required.

How to Spot a Skimmer

• Wiggle the card reader before use — overlays often feel loose
• Look for unusual protrusions or color mismatches around the card slot
• Check for a hidden camera near the PIN pad
• Use contactless payment (tap-to-pay) when possible — these can't be skimmed
• Trust your instincts — if something looks off, use a different terminal

For Business Owners

• Inspect your terminals regularly
• Enable tamper alerts if your terminal supports them
• Upgrade to NFC/contactless-capable terminals
• Work with a processor that monitors for fraud patterns

Merchant Focus provides advanced fraud protection for all merchant accounts. Contact us to learn more.