Gwynedd police and the county council are working together to reduce antisocial behaviour on buses across the county.
Posters will be placed in electronic displays and buses that run through Caernarfon, warning passengers that abusive or inappropriate behaviour will not be tolerated, and CCTV will be shared with police.
The campaign follows reports of antisocial behaviour, hate-related, sexual and public order offences.
Officers will also board buses to improve customer and staff safety, and reassure anyone who feels vulnerable.
Sergeant Rebeca Hughes said: “Many members of the public rely on public transport, including the elderly and schoolchildren.
“They should not have to witness or be subject to intimidating or threatening behaviour.
“In the last 12 months, we have received numerous reports of bus drivers being assaulted after challenging inappropriate behaviour on buses, which is completely unacceptable as they are just doing their job.
“We believe posters on permanent display send a clear message to the community that neither the police, council or bus companies will tolerate antisocial behaviour of any kind, and perpetrators will be held accountable.”
Cllr Criag ab Iago, Cabinet Member for the Environment, said: “It’s heartbreaking to see incidents of anti-social behaviour and criminal damage in our communities, especially on public transport, which so many rely on. There is absolutely no place for this kind of behaviour. We strongly condemn these actions and extend our deepest sympathy and support to the bus drivers and passengers who have been affected by the reckless actions of a small minority.
“We’re proud to be working closely with North Wales Police on this important campaign. We urge anyone who has witnessed or experienced such behaviour to come forward and report it. Your voice matters, and together we can send a clear message that our buses — and all public spaces — must be safe, respectful places for everyone.”