Pedro, who became a free agent after leaving Lazio when his contract expired in July, was a key member of Spain's 2010 World Cup-winning squad and started in the final as they beat the Netherlands. He also helped Spain win Euro 2012.
"I feel it is time. The time to take a step forward and begin a new chapter in my life," Pedro said in a statement on social media.
"I leave proud of having lived my dream and of all the people who stood by my side to make it a reality. Thank you, football, for making me so happy."
Pedro broke into Barcelona's first team in 2008 and flourished under Pep Guardiola, winning 20 major trophies with the Catalan club.
The Tenerife-born forward scored in Barcelona's 3-1 victory over Manchester United in the 2011 Champions League final before joining Chelsea in 2015.
He won the Premier League title in his second season at Stamford Bridge and later spent a season at AS Roma before crossing the city to join Lazio, where he spent the final five years of his career.
Pedro made 794 appearances at club level, scoring 197 goals, while he netted 17 times in 65 appearances for Spain.