László Lantos swam for SZEAC in 1958, FTC between 1959-61, and finally Bp. Spartacus in 1962-65. He won the Hungarian 200 metres freestyle title in 1959, and in 1959 and 1960, won five national relay titles with FTC. Lantos competed at the 1960 Roma Olympics in the 100 free, and the 4x200 free and 4x100 medley relays. He was a member of the national squad between 1958-61. In 1961 Lantos was sentenced to three years and two months in prison for his part in a group rape, with two fellow swimmers, of an 18-year-old girl.
Lantos later worked as a sports journalist and swimming trainer. His extended family had many Olympic connections. He married and divorced Mária Balla-Lantos, an Olympic swimmer, and Anikó Ducza-Jánosi, an Olympic gymnast. Through Balla-Lantos he became a brother-in-law of Gábor Balla, an Olympic shooter. With Ducza-Jánosi he had a daughter, Gabriella Lantos, who fenced at three Olympic Games, and thus became father-in-law to Tamás Debnár, an Olympic swimmer. Lantos was also the stepfather to Zsuzsa Jánosi-Németh, who fenced at the Olympics.
|Games||Discipline (Sport) / Event||NOC / Team||Pos||Medal||As|
|1960 Summer Olympics||Swimming (Aquatics)||HUN||László Lantos|
|100 metres Freestyle, Men (Olympic)||=18|
|4 × 200 metres Freestyle Relay, Men (Olympic)||Hungary||10|
|4 × 100 metres Medley Relay, Men (Olympic)||Hungary||=9|