The 41-year-old already informed his squad of his decision to move on earlier on Friday, and the successful trainer has now publicly confirmed that he will not extend his expiring contract with Barcelona.
The club also announced that Guardiola's assistant coach Tito Vilanova will take over as head coach following the season.
The former Spain international has won three La Liga and two Champions League titles during his time as Barcelona coach, a post which he inherited from Frank Rijkaard in 2008 after previously leading the club's 'B' team.
"I want you to understand this isn't a simple decision. but I'll try to explain what I feel and I hope that people understand. I'm deeply sorry for the confusion over the last few weeks," Guardiola stated at a press conference.
"I've always wanted short contracts because the demand at Barca is so big. I lived that as a player, and I know exactly how it works. I always thought that four years is an eternity for a club. I didn't want to have a contract that will bind me to decisions I didn't want.
He also hinted that his mind has been made up for some time.
"In the autumn, I announced to the president and director of football that it was the end of my era at Barca, but I couldn't say that to the players, because it would have been too complex then," said Guardiola. "Now that we're out of the two main competitions, it's a good time to announce."
The successful coach then went on to stress that the main reason for his departure is the exhaustive nature of the job.
"Four years get everyone tired," he said. "I told the chairman that my era was nearing its end around September-October. The new coach will be able to give things I'm not able to give any more. Talking to the press and players for four years is very demanding. Perhaps we wouldn't have gone wrong, but I had a feeling that we would. I know what I'm leaving - that it's the best place, but it's the right time."
Guardiola went on to thank his players, and stressed that he needs time to recharge his battery.
"I want to thanks my players who have been responsible for everything I have had here - it's been a privilege to train them. I did it all with a lot of passion,, but I want to thank the players. Day by day, for so many years, they made it all possible"
"I don't have any energy left, I need to recharge. I need to recover the feeling that I had when I first started - time has taken its toll. I just don't feel the same - Barca don't deserve that. That's all I'm going to say. I'm going with the understanding that I've done my duty, and I'm proud of everything I did. This club is an unstoppable force. My replacement will be very able, and will do his job marvellously."
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