On 5 August 2009, it was confirmed that Piquionne would join English Premier League club Portsmouth on a season-long loan. On his Pompey debut, against Rangers at Fratton Park in a friendly, he scored two goals in a 2–0 win. Piquionne made his first Premier League start for Portsmouth on 15 August 2009, a 0–1 loss to Fulham on the first day of the season. His first competitive goal for Portsmouth came in a 4–1 League Cup win against Hereford United on 25 August 2009. He scored his first Premier League goal four days later in another 4–0 win, this time at home to Wigan Athletic. Piquionne scored 11 goals in all competitions during his stint at Portsmouth, including scoring two goals against Birmingham City in the FA Cup to ensure Portsmouth progressed to the FA Cup semi-finals. On 11 April 2010, Piquionne scored the first goal in a 2–0 win over Tottenham Hotspur to send Portsmouth into the FA Cup final for the second time in three seasons. His goalscoring form at Portsmouth led Piquionne to feel as though he had finally found his feet in English football despite enduring a patchy start to his Premier League career.