Offoin competed only in the men's 100 m freestyle at the 2000 Summer Olympics in Sydney. He received a Universality place from FINA, in an entry time of 53.08. He challenged seven other swimmers in heat three, including Trinidad and Tobago's 16-year-old George Bovell and Seychelles' three-time Olympian Kenny Roberts. He cleared a 53-second barrier, and established a Nigerian record of 52.91 to race for a sixth seed, finishing behind Bovell by a hundredth of a second (0.01). Offoin failed to advance into the semifinals, as he placed sixtieth overall in the prelims.