Some demonstrators had even claimed they would throw inflatable crocodiles into the canals leading to the Scuola Grande della Misericordia to block celebrity guests arriving on gondolas.
“Bezos is on the run — this is a crazy victory for a small group of people with no money who went up against one of the richest men on the planet,” said protester Tommaso Cacciari, according to The Times.
It came as Mr Bezos held a foam party on board his yacht alongside Ms Sanchez he prepared for the lavish wedding.
Dozens of private jets are expected to arrive at Venice’s Marco Polo airport, bringing guests from as far afield as Los Angeles, Tanzania, London and Budapest.
But before the celebrations, which are expected to last three days, Mr Bezos and his fiancee threw a raucous foam party on board the Koru, his $500 million (£371 million), three-masted superyacht.
The yacht, which sails under a Cayman Islands flag, is anchored off an island on Croatia’s Adriatic coast. It will arrive in the Venetian lagoon this week, accompanied by a support ship, the Abeona, another mega-vessel, equipped with a helicopter pad.
Mr Bezos, 61, was photographed wearing swimming shorts, laughing and joking with his Ms Sanchez, 55, as a giant cannon blasted foam onto the deck of the Koru.
Protesters are preparing a hostile reception for the couple and the 250 guests they are reported to have invited for their three-day nuptials.
Various activist groups have coalesced under the slogan “No Space for Bezos”, a play on the billionaire’s Blue Origin.
They say that hosting the wedding is emblematic of how Venice has sold its soul to tourism at the expense of locals, who face acute housing shortages, the closure of basic services and the replacement of local businesses by trinket shops and trattorias.
They will have to face-off, however, against a rival group that is taking the opposite stance – that the wedding will bring Italy and the city millions of euros in revenue and the Amazon founder should be welcomed.
Rallying under the slogan “Yes Venice Can”, the group consists of Venetian hoteliers, restaurant owners and business associations.
The group said in a statement: “We cannot allow a noisy minority to discredit the image of this city in the eyes of the world.”
“We will put on the very best welcome for Bezos, as we always do for those who choose Venice as a holiday destination or as a backdrop to big events. Venice is a city that welcomes people – it doesn’t turn them away.”
It added that Venice had “always been a crossroads of cultures, travellers, merchants and famous people”.
More than 90 private jets are expected to fly into Venice this week, bringing Hollywood celebrities and tech tycoons from around the world.
Flight documents show a Gulfstream G650ER coming in from Los Angeles that belongs to Kim Kardashian, according to the Italian newspaper Corriere della Sera.
A flight from Tanzania will bring Paul Tudor Jones II, a billionaire hedge fund manager, while a plane from Valencia will bring David Geffen, the film producer and record company executive.
Kylie Jenner will reportedly arrive from Budapest, while Oprah Winfrey, the actor and chat show host, will fly in from New York City.
Bill Gates will come from Brussels, closely followed by Lachlan Murdoch, one of the sons of Rupert Murdoch, who will travel from London. Lady Gaga and Elton John are also reported to be coming.
On Monday, activists unfurled a giant banner in St Mark’s Square that read: “If you can rent Venice for your wedding, you can pay more tax.”
The demonstration was organised by Greenpeace and Everyone Hates Elon.
“While Venice is sinking under the weight of the climate crisis, billionaires are partying like there is no tomorrow on their mega-yachts. This isn’t just about one person – it’s about changing the rules so no billionaire can dodge responsibility, anywhere. The real issue is a broken system that lets billionaires skip out on taxes while everyone else is left to foot the bill. That’s why we need fair, inclusive rules – and they must be written at the UN.”
