Below are the 25 male athletes and 25 female athletes confirmed for participation in the Marathon Swimming Event of the 2016 Rio Olympic Games
| MEN | |
|---|---|
| USA | WILIMOVSKY Jordan |
| NED | WEERTMAN Ferry |
| GRE | GIANNIOTIS Spyridon |
| USA | RYAN Sean |
| GBR | BURNELL Jack Rex David |
| FRA | OLIVIER Marc-Antoine Daniel Frede |
| ITA | RUFFINI Simone |
| CAN | WEINBERGER Richard |
| BRA | DO CARMO Allan |
| ITA | VANELLI Federico |
| CHN | ZU Lijun |
| GER | REICHERT Christian |
| ECU | ENDERICA OCHOA Ivan |
| RUS | DRATTCEV Evgenii |
| TUN | MELLOULI Oussama |
| SVK | NAGY Richard |
| AUS | POORT Jarrod |
| JPN | HIRAI Yasunari |
| RSA | HO Chad |
| BUL | AYDARSKI Ventsislav |
| HUN | PAPP Mark |
| VEN | MALDONADO Erwin |
| NZL | RADFORD Kane Rae Francis |
| KAZ | KHUDYAKOV Vitaliy |
| EGY | ELAMRAWY Marwan Ahmed Aly Morsy |
| WOMEN | |
|---|---|
| FRA | MULLER Aurelie |
| NED | VAN ROUWENDAAL Sharon |
| BRA | CUNHA Ana Marcela |
| ITA | BRUNI Rachele |
| BRA | OKIMOTO Poliana |
| GER | HARLE Isabelle |
| GRE | ARAOUZOU Kalliopi |
| USA | ANDERSON Haley |
| HUN | RISZTOV Eva |
| HUN | OLASZ Anna |
| CHN | XIN Xin |
| GBR | PAYNE Keri-Anne |
| ECU | AREVALO Samantha |
| AUS | GUBECKA Chelsea |
| JPN | KIDA Yumi |
| RSA | WEBER Michelle |
| POL | ZACHOSZCZ Joanna |
| VEN | PEREZ Paola |
| SLO | PERSE Spela |
| CZE | PECHANOVA Jana |
| ESP | VILLAECIJA Erika |
| CAN | HORNER Stephanie |
| POR | NEVES Vania |
| MAS | GAN Heidi |
| EGY | KASEEM Reem Mohamed Hussein Elsayed |