On 27 February 2015 the Government published regulations for the microchipping of dogs. These regulations apply to all dogs. The time table for the implementation of microchipping is:
• Pups – born after 1st June 2015 must be microchipped upon reaching age of 12 weeks.
• Adult dogs – from 31st March 2016
The microchips implanted in dogs must be in accordance with a specified standard and are approximately the size of a grain of rice. They must be implanted by a vet, veterinary nurse or other appropriately trained persons. The microchip codes must be recorded on one of a number of approved databases which will be available to animal wardens, gardai, local authority staff and animal welfare organisations to assist them in re-uniting dogs with the owners.
A database operator must provide a dog owner with a certificate of registration. Changes of ownership must be registered with the database operator and a new certificate will be issued to the new owner. The database operator must also be informed of events such as changes address of owner or location of dog, loss of dog and death of dog.
Full details can be found here