Walt Disney World banned an ex-Marine from the Upper West Side from all its parks last week for waving a “Trump 2020” banner on Splash Mountain, he says.

“Forty Disney employees escorted me out,” recalled Dion Cini, 49.

“I held up the sign for two seconds so I can take a picture,” he told The Post. “You’re allowed to hold up signs on Disney rides — cameras, cellphones, and other stuff like that. People have been doing it for years. They just kicked me out ’cause of the context of the sign.”

Cini, an annual pass-holder with over 1,000 days in the parks, shared the news of his banishment on Facebook — along with a note from the Orange County Sheriff’s Office, outlining the requirements.

“Trespassed from all of Walt Disney World properties to include, but not limited to, Theme Parks, Water Parks, Resorts and Disney Springs,” the order says.

According to Disney rules, “unauthorized events, demonstrations or speeches, or the usage of any flag, banner or sign for commercial purposes, or to incite a crowd” is prohibited.

Cini had been temporarily banned from Disney World property in 2017 for a similar incident, but management eventually decided to let him back in. He noted how that stunt involved a 20-foot “Trump 2020” banner and was done in a much more public place — just outside of the Main Street Railroad Station in Magic Kingdom.

“The first time might have been borderline inciting the crowd, and they called me back and said they’d let me in,” Cini explained. “The second time, I just help up a small sign…and I did not incite a crowd. So I actually proved my own theory. That they kicked me out ’cause of the context of the sign and not the policy.”

Disney insists, though, that Cini’s dismissal was not about the content of the banner or a political issue.

“Walt Disney World welcomes all Guests to enjoy our parks,” a spokesperson said in a statement to The Post on Tuesday. “However, demonstrations and the display of signs and banners is not permitted on the premises.”

The spokesperson explained that flags being held on attractions that have drops or operate at high speeds are considered harmful to other guests and unsafe to the operations of the attraction.

“We have previously reminded this guest about our rules,” the spokesperson said.

In addition to Disney, Cini has also turned heads locally with his support of the president. The longtime New Yorker regularly rows up and down the Hudson River in an 18-foot scull — while flying his trademark “Trump 2020” flag.

“I like to call it guerrilla marketing,” he said, noting how there’s other plans currently in the works. “I don’t want to say, but I do have a new banner — and it’s three times bigger than the [Main Street] one.”

Cini told The Post that he chose to target Disney because he’s “just not happy with them and the way they treat the president.”

Disney’s CEO, Bob Iger, has been a vocal critic of the commander-in-chief, to the point where he quit his position on the White House advisory councils last year after Trump exited the Paris climate accord.

“As a matter of principle, I’ve resigned from the President’s Council over the #ParisAgreement withdrawal,” Iger tweeted at the time.

Cini believes his latest stunt proves that Disney is out to get Trump.

“I’d say the mission was accomplished,” he told The Post. “Time to move on to other channels.”