Microchip
A rice-grain-sized RFID chip injected under the skin between the shoulder blades. Holds a unique ID number linking to the owner's contact details in a national registry.
Microchipping is a permanent identification method that survives lost collars, faded tags, and changes of address. The chip is injected between the shoulder blades with a slightly large needle — most pets react less than to a vaccine — and is readable by any vet, shelter, or council scanner.
The chip itself stores only an ID number. That number is registered in a national database with your contact details. Two critical things owners forget: keep the registered details current (when you move, when you change phone numbers) and confirm the chip is actually registered to you (rescue dogs sometimes still show breeder or rescue details).
Microchipping is legally required in most Australian states, New Zealand, the UK, and many other jurisdictions. Without a microchip, recovery of a lost pet is much harder; with one, the chance of reunion is high.
Microchips do not provide GPS tracking — they only respond to a scanner held against the skin. For real-time location, GPS collars and AirTag-style trackers are separate products.