Some homes in Jersey can now access broadband speeds which are up to 50 times faster than before.
Flats in the new Castle Quay development in St Helier are the first place to have access to Jersey Telecom's 1GB fibre broadband service.
Jersey Telecom said this was the fastest residential broadband connection outside of South Korea.
The government owned company are spending £40m over the next few years.
Graeme Miller, chief executive officer at Jersey Telecom, said: "We don't think anyone else is doing this at the moment.
"One of the most difficult things is demonstrating the speed because we have not been able to find any commercial sites that provide a gigabit link that people can use."
Mr Miller said the service was currently being trialled and he could not confirm how much it would cost customers in the future.
He said it could be in the region of £100 per month for a 1GB connection.