Alatimu was born in Samoa and attended James Cook High School in Manurewa, New Zealand. Alatimu entered the Samoan national team pathway at the U20 level and played in the IRB Junior World Championship in 2012-13, playing four matches at the tournament and scoring 28 points. The young playmaker moved to Australia for opportunities there. In 2016, Alatimu helped Perth Spirit win the 2016 National Rugby Championship (NRC) title. His next move was to Brisbane where he joined club side GPS for the offseason and then was named to Brisbane City’s team for their 2017 NRC season. Performing well for Brisbane, Alatimu was brought into Samoa’s November Internationals squad and make his test debut against Scotland. He progressed to a Super Rugby opportunity back in Perth with Western Force where he played from 2018 through 2020. Alatimu continued to be involved in Samoa’s set up, named to the 2019 Pacific Nations Cup and later in the year, named to the World Cup side. His last test debut was against Russia in the 2019 World Cup.