However, it was only when he was 15 years old, and the coach Fausto Alonso arrived to form a serious team in Yara Clube in Marília, that Tetsuo began to train in a good pool under the guidance of someone with knowledge of swimming.

By early 1949, aged 17, Tetsuo had climbed several positions in the Brazilian national ranking, and entered the South American Championship in Montevideo, his first international competition.

[2] In 1949, a Japanese team (the 'Flying Fish') toured Brazil, and competed in Marília with excellent results, including victories over the Americans.

[6] After leaving swimming, Okamoto moved to the United States for several years, where he studied geology and business administration and started a company drilling artesian wells.

[7] He died in his city of birth, Marília, on 1 October 2007, due to heart and respiratory failure, caused by long-standing kidney problems which forced him to have frequent hemodialysis in the last years of his life.