Yes. This is mandatory. The Animal Management (Cats and Dogs) Act 2008 requires all cats and dogs to be microchipped by 12 weeks of age or when transferred to a new owner.
Part of being a responsible pet owner is getting your pet microchipped. This way, in case of escape, they are able to be swiftly retrieved if a person drops them at a Vet with a microchip scanner and your name and address appears on their screen when they look you up on the microchip register.
You can get your local Vet to implant a microchip under their skin. Search for my local Vet.