Radiofrequency identification (RFID) tags represent a wire-free alternative to guidewire localisation of impalpable breast lesions prior to surgery. The currently available RFID system is the LOCalizer™, a 10.6 × 2 mm passive RFID tag pre-loaded into a 12 G introducer needle. The handheld tag reader gives a real-time detector-to-tag distance in millimetres facilitating accurate localisation of the target lesion. Each tag carries a unique five-digit identification number, allowing discrimination between tags when multiple devices are inserted into the same breast. The reader contains a built-in loop probe for tag detection during insertion and preoperative checks, and also has an attachable sterile single-use pencil probe for precise intraoperative localisation. Like other wire-free localisation devices, RFID tags can be inserted well in advance of the date of surgery, which has advantages for both the patient and the logistics of the breast service. A growing body of evidence supports RFID tags as effective for localising breast cancers prior to surgery, with high success rates in radiological deployment and surgical retrieval. Positive margin rates and re-excision rates are comparable to guidewires and other wire-free alternatives. Although not currently licensed for axillary use, there are numerous studies demonstrating the safety and effectiveness of using RFID tags to target lymph nodes. The main potentially modifiable drawback is the size of the tag, which necessitates a 12 G introducer, and can present challenges in device deployment, especially in dense breast tissue. A narrower tag, and hence a smaller gauge introducer, would make significant improvements in its practicality.