A joint operation by West Midlands Police and partner groups saw a day of action to check people at Wolverhampton bus station were following the government guidelines on wearing masks.
One person was fined £200 for failing to comply to rules, while another 90 were instructed to wear their face mask correctly.
The force said it would continue to work with its partners at the local authority, transport operators and alongside officers from Safer Travel to monitor the city’s public transport in the weeks ahead.
Superintendent Simon Inglis said: "We’re pleased the vast majority of people are wearing face masks, but unfortunately some are still not following the rules.
"We’ve found some who have one, but are not properly covering their nose or mouth and we’ve instructed them on how to wear it correctly.
"We need people to keep following the Government regulations but if they do flout the rules we will continue to issue fines to ensure compliance and protect the city.
"Although this was a day of action, we will be routinely monitoring buses and trams across the whole of Wolverhampton in the days and weeks ahead."
John Denley, Wolverhampton’s Director of Public Health, offered his thanks to West Midlands Police for the operation and asked for people to take the rules seriously.
He said: "The vast majority of people are doing their bit and following the guidance to help protect themselves and their loved ones from the spread of the virus.
"However, we’re aware that some people are still not doing simple things like wearing face coverings on public transport which could potentially endanger others.
"We welcome this operation by West Midlands Police and hope it sends a message that we’re all in this together and won’t tolerate people breaking the rules."