The last day Georgia voters can request absentee ballots for the presidential election is Friday, but slow mail delivery times pose a risk that ballots won’t be returned in time.

Georgia law allows all registered voters to apply for an absentee ballot until 11 days before an election day. To be counted, ballots must be received by county election offices before polls close at 7 p.m. on election day.

The U.S. Postal Service says it is taking “extraordinary measures” to ensure ballots are transported in time. Still, there’s no guarantee that last-minute absentee voters will have enough time to receive and return their ballots.

Voting rights advocates are encouraging Georgia voters to vote in person. Early voting lasts until Nov. 1, and neighborhood polling places will be open statewide on Election Day, Nov. 5.

“If you haven’t sent your mail ballot back, we recommend you either take it to a drop box or vote early in person,” said Max Flugrath, spokesman for the voting organization Fair Fight. “If you have to mail it back, use a priority mail service with a tracking number.”

So far, about 320,000 voters have requested absentee ballots and 149,000 have been returned. Those are much smaller numbers than in 2020, when 1.3 million people cast absentee ballots during the COVID-19 pandemic.

Meanwhile, in-person early voting has surged, with turnout approaching 2.25 million through Thursday.

Voters can request an absentee ballot through the state’s My Voter Page. They can then email their filled-out absentee ballot request to their county’s election office, or they can scan and upload the form through the My Voter Page.

Ballots can be returned through the mail, delivered by hand to county election offices or deposited into ballot drop boxes, which Georgia’s 2021 voting law limited to early voting locations.

Voters who requested an absentee ballot can still vote in person. Election officials say voters should bring their absentee ballots with them if they decide to instead vote at a polling place.