The striker told reporters after Spain's 2-2 draw with Colombia on Wednesday that the Blues boss has informed him via text message.
Chelsea striker Diego Costa says he has been told by manager Antonio Conte that he does not have a future at Stamford Bridge.
The striker has been linked with a move away from the Premier League champions for much of the past season, despite having scored 22 goals in all competitions.
Costa was tipped for a move to the lucrative Chinese Super League in January only to commit to Chelsea for the remainder of the campaign, but his future has been cast into fresh doubt since reports emerged linking the Blues with a bid for Everton striker Romelu Lukaku.
The 28-year-old Costa has now stated that Conte has informed him he is free to look for another club and believes his dip in form in the second half of the season is behind the decision.
"I had a simple little message on my mobile from Conte in which he said that he isn't counting on me for next season," Costa told the media following Spain's 2-2 friendly draw with Colombia on Wednesday.
"It will be because I've done badly this year. It's a shame. I've forwarded the message on to the people at the club for them to decide but it's clear that the coach isn't counting on me and he doesn't want me there.
"I'm on the market and so I'm looking for a team. If the coach doesn't want you, you have to leave."
Costa has been linked with a potential move back to Atletico Madrid but he says a return is complicated by the LaLiga club's transfer ban.
The Court of Arbitration for Sport (CAS) refused to uphold Atletico's appeal against a ban on registering new players handed down by FIFA, which means they will be unable to field any new signings until January next year.
"It would be nice to go back to Atletico but I have to think everything over," he said. "There's a World Cup [in 2018] and I need to play. Being four or five months without playing is tough, but people know that I love my Atletico team-mates a lot, I love living in Madrid."