The deal is reportedly worth €90 million ($98.24 million) plus add-ons, making it the most expensive transfer in Saudi Arabian football history.
Neymar got four Mercedes G Wagons for his entourage, and a Mercedes van with a driver.
Neymar has also asked for three saunas to be installed in his house and a sous chef to help his personal Brazilian chef.
Neymar is expected to make his debut for Al-Hilal in their next league match on August 27 against Al-Faisaly.
"I am excited to join Al-Hilal and to be a part of their history. I want to help the team win more trophies and to achieve their goals. I am also looking forward to playing in the AFC Champions League."
"We are delighted to welcome Neymar to Al-Hilal. He is one of the best players in the world and he will be a great asset to our team. We are confident that he will help us achieve our goals."
Neymar, 31, leaves Paris Saint-Germain after six years, during which time he won five Ligue 1 titles and the Coupe de France three times.
The influx of star players is seen as a way to boost the popularity of football in Saudi Arabia and to attract more fans from around the world