Dopey tourists are paying top dollar to bogus vendors for “tickets” to the Staten Island Ferry — which has been free for 18 years, The Post has learned.

One clueless pair shelled out $400 for a round-trip journey to the city’s southernmost borough, sources said.

“They’re targeting people who are tourists, because they just don’t know better,” said a source with the city’s Parks Enforcement Patrol.

Career con Gregory Reddick, 54, hooked the big fish on Wednesday while wearing a snappy “Authorized Ticket Agent” jacket near the South Street Seaport, officials said.

“Usually, the people we’re seeing are complaining that they’ve been charged $25” for a Staten Island Ferry ride, said the parks-enforcement source.

“But this guy was charging $200 each way.”

Reddick, of Jamaica, Queens, was caught by Parks Enforcement Patrolman Jean-Baptist Joseph, 33, on Pier 15 as he allegedly took the cash from the two marks.

When Joseph asked to see an ID and Parks permit, Reddick shoved him in the chest and took off, a criminal complaint says.

Joseph chased Reddick to The Battery, where he and a half-dozen fellow officers surrounded the 200-pound suspect, subduing him with the help of pepper spray, the complaint says.

He allegedly still had the $400 on him, but the two tourists were already gone and the cash could not be returned, a source said.