The confirmation comes a day after the star player's cancellation of his contract with Al Hilal.
The length of Neymar's contract has not yet been officially confirmed, but it should be just five months. He returns home in search of a career comeback, after suffering from serious injuries in recent seasons.
"The time has come to build our new story. Return to your home, we have open arms," said Teixeira on his Instagram account, ahead of the club's own announcement.
Neymar's debut for Santos should take place on his birthday, February 5th, when he turns 33. They face Botafogo-SP at Vila Belmiro.
Since the 2022 World Cup, Neymar has only played 20 games in just over two years.
Signed from Al Hilal for 90 million euros in August 2023, the attacking midfielder made just seven official appearances for the Saudi club, with one goal and two assists.
Passed over by coach Jorge Jesus, Neymar wasn't even registered for this season's Saudi League and has only played in two AFC Champions League matches this season, against Al Ain and Esteghlal.
Neymar is one of the great idols in Santos' history and made his mark at the Vila between 2009 and 2013, with 225 appearances, 136 goals and 63 assists.
He won six trophies for Peixe: Libertadores (2011), Recopa Sudamericana (2012), Copa do Brasil (2010) and three Paulistas (2010, 2011 and 2012).
Sold to Barcelona in 2013, Neymar formed part of the legendary 'MSN' trio and shone at the Spanish club, winning two La Liga titles and the Champions League.
Paris Saint-Germain bought Neymar in 2017 for 222 million euros, the most expensive transfer in football history.