Up to 2,000 of its 4,000 smartphone business staff could lose their jobs by March 2020, including employees in Japan, Europe, and China.
The move comes as Sony's 2018 fiscal year is expected to show just 6.5 million smartphone sales, which is half its 2017 figures and a sixth of its sales figures from five years ago.
Sony cut its smartphone workforce by 1,000 employees in 2014, but the plummeting sales figures have meant that more cuts are needed.
Sony's smartphone business is also expected to post an operating loss for the third year in a row in 2019.
In March, Sony announced its intention to continue its smartphone business, which prompted Sony shares to plummet to a 17-month low.