Nearly a year ago, the Florida senator launched his campaign here with a soaring speech at the Freedom Tower, a building that was used to process Cuban refugees fleeing the Castro regime decades ago.
But in the days ahead of a contest that could end his campaign, Rubio has instead been making urgent appeals to his constituents to support him once again as he tries to take out Republican front-runner Donald Trump.
"We have to win here in Florida," Rubio said at a recent event in Hialeah, seemingly begging the crowd. "Hialeah believed in me (in 2010). I'm asking you to believe in me now."
"I am focused on one thing right now," he told reporters a few days later at a synagogue in West Palm Beach, and that is winning the state of Florida, and then moving on in my campaign."
He's even working to appeal to voters who may not support him -- but are against Trump.
"I'm telling people in Florida the truth: A vote for Ted Cruz or a vote for John Kasich in Florida is a vote for Donald Trump," Rubio said in West Palm Beach. "Any vote that doesn't go to me in essence is helping Donald Trump to win. ... If Donald Trump wins by one vote, he will take 99 delegates."
It's a far cry from the start of the campaign for the native son, who throughout the campaign has leaned heavily on his autobiography of growing up the child of two Cuban immigrants mostly in Southern Florida. But that narrative has struggled to resonate after Trump took the GOP race by storm.
So far, Rubio has managed to win just three contests in the 2016 primary season.
Going into Super Tuesday 3, Rubio is trailing Trump in Florida by double digits, 40% to 26%, according to CNN's poll of polls
. He's down in the delegate race by more than 200 to Trump, a gap that can't be closed by Florida's winner-take-all contest alone.
Still, some of his supporters say they aren't discouraged.
"There is no worry," said Yeybarth Lopez, a young IT professional who drove down from Tennessee to volunteer in Florida for Rubio. "All eyes on Florida right now. We can't wait for him to win."
A Venezuelan, she compared Trump to the late dictator Hugo Chavez, and said that's a message that resonates with immigrants from authoritarian countries.
"Venezuelans fear that Trump is going to be like the next Chavez, the way that Chavez the Venezuelan president, the way he won people is by lying and saying those politicos are incorrect and you don't need another politician anymore, choose me. And that is what Trump is doing," she said.
But other supporters were very aware their candidate is struggling in the polls.
"We're hoping and praying that people wake up and just think hard about our future as a country, and the way the polls are looking, it's very concerning," said Stephanie Christiansen, a stay-at-home mom from Davie, Florida. "Anything is possible. If I didn't think there was any hope, I wouldn't be here."
"Anything is possible," echoed Daniel Tyson, a Naval science instructor and veteran from Broward County. "It's going to be close."
His girlfriend, Miami personal trainer Jennie Bakker said she was ""very worried right now."
"I think Trump getting the win is definitely going to be devastating," she said. "Just worried, hoping for the best, praying for the best."
Rubio was even greeted by a doubter at a retail stop in Naples, Florida, who held up a sign encouraging him to throw his support behind rival Texas Sen. Ted Cruz.
"Sen. Rubio, THE TEA PARTY & I ELECTED you and SEN. Cruz. Please endorse Ted before March 15. Your time will come soon," read the homemade sign from John Moore.
Pulling out the stops
Volunteers have poured into the state from across the country. Like Lopez, a man from Seattle was at the Hialeah rally, piggy-backing a volunteer trip on business travel. Another volunteer from New York was helping to staff the Miami office on Thursday afternoon as phone bankers in English and Spanish diligently made their calls.
"Darling, fire under your a--," one woman said emphatically in a call to a friend. "We have to win Florida," she said. Call "everyone" and get them to volunteer, she added.
Campaign spokesman Alex Burgos estimated hundreds if not thousands of volunteers are being deployed in the state, not to mention millions in on-air buys by the Rubio campaign and a supportive super PAC.
Rubio is hitting all parts of the state, from the Panhandle to the southern counties. But the campaign is banking heavily on running up the score in South Florida, where Rubio leads in the polls, to help offset Trump's strength in central and northern parts of the state.
The campaign has also been making a concerted effort to encourage voters to either cast their ballots early or absentee. Rubio led Trump 48% to 23% among the nearly 20% of voters who had already voted, according to a Monmouth poll
"I think he's going to get a very strong turnout in Miami-Dade County," Florida Rep. Carlos Curbelo told reporters after the CNN Republican debate in Miami on Thursday night. "I think Hispanic Republicans are already turning out in very high numbers and that is going to continue. ... And Marco Rubio has a great shot. Is it going to be close? Absolutely, but he's still in it."
His supporters are quick to say that the county has more Republicans than any other in the state, as well.
"I think you're going to see the Miami-Dade turnout be something of historic proportions," Rubio's Florida Co-Chairman Adam Hasner said in West Palm Beach.
Miami-Dade GOP Chairman Nelson Diaz, who supports Rubio in a private capacity, gave Rubio a slight edge to win.
"I think Marco's got a 60% chance of winning Florida," Diaz said. "I think it's clearly between him and Trump, and the question is how much damage did Ted Cruz do (with advertising) in the last week before the end."
"It's not over until it's over," former Florida Rep. Lincoln Diaz-Balart said, channeling Yogi Berra, as he warmed up and tried to encourage the crowd in Hialeah.
Rubio, for his part, is fond of saying he's an "underdog," noting that he chased an incumbent governor out of the Republican primary to win his Senate seat six years ago.
He's discounting the polls showing him down in most cases by double digits -- citing a state he ultimately lost by three points as evidence.
"Polls were wrong in Virginia," Rubio said in West Palm Beach, noting that the surveys showed him trailing by a wide margin before his close second place. "I would have beat (Trump) if I had another two days of campaigning," he added.