Midhurst and Petworth’s main public transport links will be severed if threatened county council cuts go ahead.
There are concerns the two towns at the heart of the new South Downs National Park will be cut off on Sundays, the most popular visitor day of the week.
Now community leaders are being urged to make their voices heard in a bid to stop the proposed cuts going ahead.
The biggest threat to Midhurst is the plan to scrap the 60 service from Midhurst to Chichester and Bognor on Sundays and in the evenings as West Sussex County Council strives to save £79m.
North Street resident Deborah Camp-Simpson is among a group of Midhurst residents who oppose the plans.
“This will affect our tourist trade,” she said. “Tourists decant from the buses in their droves on Sundays and how are they going to get here if this artery to the heart of the downs is severed?
“How are young people going to get to the cinema or to weekend jobs in Chichester if they can’t get home in the evenings?”
And at Petworth, town councillor Gordon Allan said he was concerned about threats to the No 1 service from Worthing to Midhurst on Sundays and in the evenings.
“This would mean no public transport available from Petworth to anywhere at all on Sundays,” he said. “This would mean people could not get to Pulborough station to get to London or to Storrington or anywhere between Petworth and Midhurst.”
He is also concerned about plans to reduce the frequency of the 75 and 76 Petworth to Horsham service which would make it more difficult to access trains from Billingshurst.
Other services under threat include the X92 Midhurst to Portsmouth Saturday service and fewer buses on the 91, 92 and 93 Midhurst to Petersfield route.
All these services depend on grants from the county council to pay their costs and now an impact assessment has begun to find out how scrapping the subsidised services will affect passengers.
The savings will start from this September, but will be phased in over three years. Passengers have been asked to explain by June 10 how the changes will affect them.