Cyclists in Jersey aged under 14 will now be forced to wear helmets or risk a £50 fine, after the law was changed by politicians.
The country has long lobbied for tighter laws but previous attempts to make helmets mandatory for all riders have failed.
The change in the law was brought by transport minister Deputy Kevin Lewis and voted through by States Members.
Deputy Lewis said it was unlikely that fines would be enforced but told the BBC: "It is my wish and desire that once young people get into the habit of wearing a cycle helmet for a number of years, they would wish not to take them off later on."
The proposition was first mooted in 2010 by Deputy Andrew Green MBE, Minister for Housing.
Deputy Green, whose nine year old son received a brain injury when he was knocked off his bike said: “I am delighted that this vital piece of legislation has been passed and I congratulate my fellow Members in the Assembly for taking this bold but necessary decision.”
In 2010, politicians on the island rejected by a solitary vote a proposal to make it compulsory for all cyclists, including adults, to wear a helmet, although they approved by a margin of two to one similar measures for children aged under 18.
The move was welcomed by the brain injury association, Headway Preston & Chorley.
Liz Bamber, Headway Development Officer told the Lancashire Evening Post: “Being a keen cyclist... I am staggered by the number of people still not wearing helmets.
“It is hoped that the UK will follow Jersey’s example very soon.”