According to Official Guinness Records,
The most people in a floating line (unassisted) consists of 1,941 people and was achieved by Municipalidad Adolfo Alsina (Argentina) in Carhué, Argentina, on 29 January 2017. The record was attempted in the same lake that flooded the city of Epecuén more than 30 years ago. This attempt has brought hope and joy to the citizens of Epecuén.Full story: Over one thousand people break a flotation record in Argentina
For a complete list of 2017 records, please visit 2017 Guinness Records in Argentina.