[1] A three-time Olympian (2000, 2004, and 2008), he started his career as a double-handed dinghy sailor in Sydney, before switching to the skiff for the remaining two editions of the Games, finishing in sixth and seventh place, respectively.
There, he and his partner Alexandre Paradeda finished twenty-sixth in the men's 470 class with a net grade of 171, sparing them from the sterns of the fleet by a 33-point edge over the Hungarian duo of Marcell Goszleth and Ádám Szörényi.
[4][5] Fonseca switched to the skiff boat with his new partner Rodrigo Duarte and eventually surprised the 19-crew fleet with a spectacular sixth overall position in the 49er at his second Olympiad in Athens 2004, amassing 104 net points.
[7] The Brazilian pair finished eleventh in the golden fleet to secure one of the five remaining spots vying for qualification at the 49er Worlds eight months earlier in Sydney, Australia.
Under gusty conditions and heavy rainfall, however, the Brazilians struggled to chase the rest of the fleet on the final run and never looked back, fading steadily to seventh overall with 99 net points.