A very close race in Israel's election on Tuesday has prompted many citizens living abroad to travel home to vote. Israel does not permit voting from overseas, with the exception of people serving in the country's diplomatic missions.

One group helping to organize expatriates estimates that as many as 80,000 Israelis living outside the country will return to take part. The International Foundation for Electoral Systems, based in Washington, says Israel has about 7.3 million eligible voters. Yael Shomer, a professor of political science at Tel Aviv University, said the returning voters are "not a large block," but could "make a big difference in the final count of a very tight election."

It is Israel's first election since 2022. Benjamin Netanyahu of the Likud party, who has served as Prime Minister for 18 years over three separate periods, faces his top challenger, Gadi Eisenkot, a former chief of staff of the Israel Defense Forces who leads the Yashar party. Either man would likely need support from potential coalition partners to win.

Several divisive issues are shaping the contest. Security, already a major factor for Israeli voters, has become more contentious with the war with Iran in full swing. The exemption of some ultra-Orthodox men from military conscription is deeply dividing society, and Netanyahu is still pursuing a controversial plan that would give the governing coalition more control over the judiciary.

Shomer said the stakes have made the campaign especially intense. "This election is really about how we see our future, voter turnout will be very high," she said. Turnout in 2022 was just over 70%, according to Israel's Central Elections Committee, while pollsters think it could reach as high as 87% this time. Turnout among foreign service workers at embassies and consulates was 90%, compared with a usual figure closer to 70%, the committee said.

To help expatriates return, an organization called Fly & Vote was set up by the America-Israel Democracy Coalition, a U.S.-based group created in 2023 to oppose Likud's effort to overhaul the judicial system. Organizations and political parties are barred from paying for transportation, but the coalition found other ways to assist voters.

Funded by private donations, Fly & Vote chartered a flight for Israelis living in Portugal and bought blocks of tickets on flights from the New York area. Passengers paid for their own seats. Co-founder Ora Peled-Nakash said: "We don't take a political position though and we don't tell anyone how to vote, we just help them cast their ballot."

Travelers also have many commercial options. El Al was for decades the only Israeli airline on U.S.-Israel routes, but Arkia began service last year and Israir earlier this year. United and Delta have resumed flights after suspending them because of the war with Iran, Lufthansa flies to Israel from Europe, and British Airways is scheduled to restart service this week. Peled-Nakash said prices are in line with normal times. As of Sunday, CNBC found a few seats left on El Al flights from JFK or Newark airports priced between $1,300 and $2,500.

Israel held five elections between 2019 and 2022, and the result of this one could shape the country's political, security and economic direction for years. It also underscores how politically divided the country has become.