MILAZZO, Sicily — For Italian politicians, it’s high season in Sicily.

Days before the southern island votes in regional elections on Sunday, the country’s ambitious and warring political protagonists have turned it into a political theater, hoping that a good showing by their coalition partners will sway national elections set for next year.

Former Prime Minister Silvio Berlusconi, 81, returned — with less weight, more hair and tighter skin — to his former electoral stronghold to warm his hopes of a political comeback, casting himself in a new persona as a wise old moderate for polarized times.

Another former prime minister, Matteo Renzi, whose Democratic Party is expected to lose big, braved a brief appearance on Friday despite concerns that the island’s voters could dent his own political comeback. Mr. Renzi then spent the last crucial campaign days far away, meeting with Barack Obama in Chicago.

But among all the competing forces, it is the Five Star Movement’s leaders, including its co-founder Beppe Grillo, who have most eagerly swarmed Sicily, looking to seize on their last and best opportunity to build momentum before national elections in early 2018.