Ka cika wannan furcin: A Wasannin Olympics na 2004 a Athens, Alleyne ya ci gaba da shirinsa ta wajen cancanta a wasanni biyu na iyo. Ya share FINA B-misali shigarwa sau na 51.89 (100 m freestyle) da kuma 1:53.19 (200 m freestyle) daga Pan American Games a Santo Domingo, Jamhuriyar Dominica. A cikin mita 200 na 'yanci, Alleyne ya kalubalanci wasu masu iyo bakwai a zagayen na uku, gami da' yan wasansa biyu na Olympics Joshua Ilika Brenner na Mexico da Giancarlo Zolezzi na Chile. Ya shawo kan Mahrez Mebarek na Algeria don ɗaukar matsayi na uku da na talatin da huɗu gaba ɗaya da 0.11 na biyu a cikin 1: 52.89. A karo na biyu,
100 m freestyle, Alleyne ya sanya na arba'in da takwas a gaba ɗaya a farkon safiya. Yin iyo a zagaye na uku, Alleyne ya dace da lokacin shigarsa na 51.89 don adana matsayi na biyar a kan ɗan ƙasar Zolezzi Max Schnettler ta 0.02 na biyu.