The 21-year-old is expected to sign his contract on Monday after making his farewell appearance in the Brazilian league on Sunday night. Neymar has been courted by both Barcelona and Real Madrid since 2011, with both Spanish clubs believed to have had bids of around £21.3 million accepted.
Neymar used his Instagram account on Saturday night to confirm he will be heading to the Nou Camp.
"I'm here with friends and family and they have helped me to write a few things," he said.
"I'm not going to hold out until Monday. My family and friends already know my decision. On Monday I will sign a contract with Barcelona."
Neymar's current deal with Santos was due to expire after the 2014 World Cup in Brazil. Chelsea and Manchester City were both thought to have been interested in signing him.
Meanwhile, Radamel Falcao's proposed £51m transfer to Monaco from Atletico Madrid could also be completed today. Reports from Spain suggested that the Colombian would fly to the south of France for his medical and then link up with his former Porto team-mates Joao Moutinho and James Rodriguez, who joined the newly promoted club on Friday for a combined fee of around £60m.