Thai Navy Seal, Petty Officer Beirut Pakbara, died from an infection he contracted during the operation.
Officer Beirut was part of the rescue team that saved 12 boys and their soccer coach from a flooded cave last year.
In a statement Friday, The Thai Royal Navy expressed their condolences to his family.
Beirut contracted a blood infection during the rescue operation at Tham Luang Cave in northern Thailand.
He was under medical supervision, but his condition worsened after the infection got into his bloodstream.
He died on Friday, according to the Thay Royal Navy.